diff --git a/_pydemo/print/print.go b/_pydemo/print/print.go
new file mode 100644
index 00000000..5401c00f
--- /dev/null
+++ b/_pydemo/print/print.go
@@ -0,0 +1,11 @@
+package main
+
+import (
+	"github.com/goplus/llgo/py"
+	"github.com/goplus/llgo/py/std"
+)
+
+func main() {
+	x := py.Float(3.14)
+	std.Print(x)
+}
diff --git a/_pydemo/tensor/tensor.go b/_pydemo/tensor/tensor.go
new file mode 100644
index 00000000..310c37c0
--- /dev/null
+++ b/_pydemo/tensor/tensor.go
@@ -0,0 +1,16 @@
+package main
+
+import (
+	"github.com/goplus/llgo/py"
+	"github.com/goplus/llgo/py/std"
+	"github.com/goplus/llgo/py/torch"
+)
+
+func main() {
+	data := py.List(
+		py.List(1.0, 2.0),
+		py.List(3.0, 4.0),
+	)
+	x := torch.Tensor(data)
+	std.Print(x)
+}
diff --git a/chore/llpyg/llpyg.go b/chore/llpyg/llpyg.go
index 88e6ff1b..c455781b 100644
--- a/chore/llpyg/llpyg.go
+++ b/chore/llpyg/llpyg.go
@@ -131,7 +131,7 @@ func (ctx *context) genMod(pkg *gogen.Package, mod *module) {
 			ctx.genFunc(pkg, sym)
 		case "str", "float", "bool", "type", "dict", "tuple", "list", "object", "module",
 			"int", "set", "frozenset", "flags", "bool_", "pybind11_type", "layout",
-			"memory_format", "qscheme", "dtype", "tensortype": // skip
+			"memory_format", "qscheme", "dtype", "tensortype", "ellipsis": // skip
 		case "": // pysigfetch: page not found
 			ctx.skips = append(ctx.skips, sym.Name)
 		default:
diff --git a/py/builtins/llgo_autogen.lla b/py/builtins/llgo_autogen.lla
deleted file mode 100644
index 3169e152..00000000
Binary files a/py/builtins/llgo_autogen.lla and /dev/null differ
diff --git a/py/builtins/builtins.go b/py/std/builtins.go
similarity index 67%
rename from py/builtins/builtins.go
rename to py/std/builtins.go
index d425e862..bfc21d08 100644
--- a/py/builtins/builtins.go
+++ b/py/std/builtins.go
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package builtins
+package std
 
 import (
 	_ "unsafe"
@@ -22,30 +22,9 @@ import (
 	"github.com/goplus/llgo/py"
 )
 
-const (
-	LLGoPackage = "py.inspect"
-)
-
 // https://docs.python.org/3/library/functions.html
 // https://docs.python.org/3/library/constants.html
 
-// print(*objects, sep=' ', end='\n', file=None, flush=False)
-//
-// Print objects to the text stream file, separated by sep and followed by
-// end. sep, end, file, and flush, if present, must be given as keyword
-// arguments.
-//
-// All non-keyword arguments are converted to strings like str() does and
-// written to the stream, separated by sep and followed by end. Both sep
-// and end must be strings; they can also be None, which means to use the
-// default values. If no objects are given, print() will just write end.
-//
-//go:linkname Print py.print
-func Print(objects ...*py.Object)
-
-//go:linkname PrintEx py.print
-func PrintEx(__llgo_kwargs *py.Object, objects ...*py.Object)
-
 // Invoke the built-in help system. (This function is intended for interactive
 // use.) If no argument is given, the interactive help system starts on the
 // interpreter console. If the argument is a string, then the string is looked
diff --git a/py/std/gen.go b/py/std/gen.go
new file mode 100644
index 00000000..f6083dcd
--- /dev/null
+++ b/py/std/gen.go
@@ -0,0 +1,396 @@
+package std
+
+import (
+	_ "unsafe"
+
+	"github.com/goplus/llgo/py"
+)
+
+const LLGoPackage = "py.builtins"
+
+// Return True if bool(x) is True for all values x in the iterable.
+//
+// If the iterable is empty, return True.
+//
+//go:linkname All py.all
+func All(iterable *py.Object) *py.Object
+
+// Return True if bool(x) is True for any x in the iterable.
+//
+// If the iterable is empty, return False.
+//
+//go:linkname Any py.any
+func Any(iterable *py.Object) *py.Object
+
+// Return an ASCII-only representation of an object.
+//
+// As repr(), return a string containing a printable representation of an
+// object, but escape the non-ASCII characters in the string returned by
+// repr() using \\x, \\u or \\U escapes. This generates a string similar
+// to that returned by repr() in Python 2.
+//
+//go:linkname Ascii py.ascii
+func Ascii(obj *py.Object) *py.Object
+
+// Return the binary representation of an integer.
+//
+//	>>> bin(2796202)
+//	'0b1010101010101010101010'
+//
+//go:linkname Bin py.bin
+func Bin(number *py.Object) *py.Object
+
+// Return whether the object is callable (i.e., some kind of function).
+//
+// Note that classes are callable, as are instances of classes with a
+// __call__() method.
+//
+//go:linkname Callable py.callable
+func Callable(obj *py.Object) *py.Object
+
+// Return a Unicode string of one character with ordinal i; 0 <= i <= 0x10ffff.
+//
+//go:linkname Chr py.chr
+func Chr(i *py.Object) *py.Object
+
+// Compile source into a code object that can be executed by exec() or eval().
+//
+// The source code may represent a Python module, statement or expression.
+// The filename will be used for run-time error messages.
+// The mode must be 'exec' to compile a module, 'single' to compile a
+// single (interactive) statement, or 'eval' to compile an expression.
+// The flags argument, if present, controls which future statements influence
+// the compilation of the code.
+// The dont_inherit argument, if true, stops the compilation inheriting
+// the effects of any future statements in effect in the code calling
+// compile; if absent or false these statements do influence the compilation,
+// in addition to any features explicitly specified.
+//
+//go:linkname Compile py.compile
+func Compile(source *py.Object, filename *py.Object, mode *py.Object, flags *py.Object, dontInherit *py.Object, optimize *py.Object) *py.Object
+
+// Deletes the named attribute from the given object.
+//
+// delattr(x, 'y') is equivalent to “del x.y“
+//
+//go:linkname Delattr py.delattr
+func Delattr(obj *py.Object, name *py.Object) *py.Object
+
+// Return the tuple (x//y, x%y).  Invariant: div*y + mod == x.
+//
+//go:linkname Divmod py.divmod
+func Divmod(x *py.Object, y *py.Object) *py.Object
+
+// Evaluate the given source in the context of globals and locals.
+//
+// The source may be a string representing a Python expression
+// or a code object as returned by compile().
+// The globals must be a dictionary and locals can be any mapping,
+// defaulting to the current globals and locals.
+// If only globals is given, locals defaults to it.
+//
+//go:linkname Eval py.eval
+func Eval(source *py.Object, globals *py.Object, locals *py.Object) *py.Object
+
+// Execute the given source in the context of globals and locals.
+//
+// The source may be a string representing one or more Python statements
+// or a code object as returned by compile().
+// The globals must be a dictionary and locals can be any mapping,
+// defaulting to the current globals and locals.
+// If only globals is given, locals defaults to it.
+// The closure must be a tuple of cellvars, and can only be used
+// when source is a code object requiring exactly that many cellvars.
+//
+//go:linkname Exec py.exec
+func Exec(source *py.Object, globals *py.Object, locals *py.Object) *py.Object
+
+// Return type(value).__format__(value, format_spec)
+//
+// Many built-in types implement format_spec according to the
+// Format Specification Mini-language. See help('FORMATTING').
+//
+// If type(value) does not supply a method named __format__
+// and format_spec is empty, then str(value) is returned.
+// See also help('SPECIALMETHODS').
+//
+//go:linkname Format py.format
+func Format(value *py.Object, formatSpec *py.Object) *py.Object
+
+// Return the dictionary containing the current scope's global variables.
+//
+// NOTE: Updates to this dictionary *will* affect name lookups in the current
+// global scope and vice-versa.
+//
+//go:linkname Globals py.globals
+func Globals() *py.Object
+
+// Return whether the object has an attribute with the given name.
+//
+// This is done by calling getattr(obj, name) and catching AttributeError.
+//
+//go:linkname Hasattr py.hasattr
+func Hasattr(obj *py.Object, name *py.Object) *py.Object
+
+// Return the hash value for the given object.
+//
+// Two objects that compare equal must also have the same hash value, but the
+// reverse is not necessarily true.
+//
+//go:linkname Hash py.hash
+func Hash(obj *py.Object) *py.Object
+
+// Return the hexadecimal representation of an integer.
+//
+//	>>> hex(12648430)
+//	'0xc0ffee'
+//
+//go:linkname Hex py.hex
+func Hex(number *py.Object) *py.Object
+
+// Return the identity of an object.
+//
+// This is guaranteed to be unique among simultaneously existing objects.
+// (CPython uses the object's memory address.)
+//
+//go:linkname Id py.id
+func Id(obj *py.Object) *py.Object
+
+// Read a string from standard input.  The trailing newline is stripped.
+//
+// The prompt string, if given, is printed to standard output without a
+// trailing newline before reading input.
+//
+// If the user hits EOF (*nix: Ctrl-D, Windows: Ctrl-Z+Return), raise EOFError.
+// On *nix systems, readline is used if available.
+//
+//go:linkname Input py.input
+func Input(prompt *py.Object) *py.Object
+
+// Return whether an object is an instance of a class or of a subclass thereof.
+//
+// A tuple, as in “isinstance(x, (A, B, ...))“, may be given as the target to
+// check against. This is equivalent to “isinstance(x, A) or isinstance(x, B)
+// or ...“ etc.
+//
+//go:linkname Isinstance py.isinstance
+func Isinstance(obj *py.Object, classOrTuple *py.Object) *py.Object
+
+// Return whether 'cls' is derived from another class or is the same class.
+//
+// A tuple, as in “issubclass(x, (A, B, ...))“, may be given as the target to
+// check against. This is equivalent to “issubclass(x, A) or issubclass(x, B)
+// or ...“.
+//
+//go:linkname Issubclass py.issubclass
+func Issubclass(cls *py.Object, classOrTuple *py.Object) *py.Object
+
+// Return an AsyncIterator for an AsyncIterable object.
+//
+//go:linkname Aiter py.aiter
+func Aiter(asyncIterable *py.Object) *py.Object
+
+// Return the number of items in a container.
+//
+//go:linkname Len py.len
+func Len(obj *py.Object) *py.Object
+
+// Return a dictionary containing the current scope's local variables.
+//
+// NOTE: Whether or not updates to this dictionary will affect name lookups in
+// the local scope and vice-versa is *implementation dependent* and not
+// covered by any backwards compatibility guarantees.
+//
+//go:linkname Locals py.locals
+func Locals() *py.Object
+
+// Return the octal representation of an integer.
+//
+//	>>> oct(342391)
+//	'0o1234567'
+//
+//go:linkname Oct py.oct
+func Oct(number *py.Object) *py.Object
+
+// Return the Unicode code point for a one-character string.
+//
+//go:linkname Ord py.ord
+func Ord(c *py.Object) *py.Object
+
+// Equivalent to base**exp with 2 arguments or base**exp % mod with 3 arguments
+//
+// Some types, such as ints, are able to use a more efficient algorithm when
+// invoked using the three argument form.
+//
+//go:linkname Pow py.pow
+func Pow(base *py.Object, exp *py.Object, mod *py.Object) *py.Object
+
+// Prints the values to a stream, or to sys.stdout by default.
+//
+//	sep
+//	  string inserted between values, default a space.
+//	end
+//	  string appended after the last value, default a newline.
+//	file
+//	  a file-like object (stream); defaults to the current sys.stdout.
+//	flush
+//	  whether to forcibly flush the stream.
+//
+//go:linkname Print py.print
+func Print(__llgo_va_list ...interface{}) *py.Object
+
+// Return the canonical string representation of the object.
+//
+// For many object types, including most builtins, eval(repr(obj)) == obj.
+//
+//go:linkname Repr py.repr
+func Repr(obj *py.Object) *py.Object
+
+// Round a number to a given precision in decimal digits.
+//
+// The return value is an integer if ndigits is omitted or None.  Otherwise
+// the return value has the same type as the number.  ndigits may be negative.
+//
+//go:linkname Round py.round
+func Round(number *py.Object, ndigits *py.Object) *py.Object
+
+// Sets the named attribute on the given object to the specified value.
+//
+// setattr(x, 'y', v) is equivalent to “x.y = v“
+//
+//go:linkname Setattr py.setattr
+func Setattr(obj *py.Object, name *py.Object, value *py.Object) *py.Object
+
+// Return a new list containing all items from the iterable in ascending order.
+//
+// A custom key function can be supplied to customize the sort order, and the
+// reverse flag can be set to request the result in descending order.
+//
+//go:linkname Sorted py.sorted
+func Sorted(iterable *py.Object) *py.Object
+
+// Return the sum of a 'start' value (default: 0) plus an iterable of numbers
+//
+// When the iterable is empty, return the start value.
+// This function is intended specifically for use with numeric values and may
+// reject non-numeric types.
+//
+//go:linkname Sum py.sum
+func Sum(iterable *py.Object, start *py.Object) *py.Object
+
+// Open file and return a stream.  Raise OSError upon failure.
+//
+// file is either a text or byte string giving the name (and the path
+// if the file isn't in the current working directory) of the file to
+// be opened or an integer file descriptor of the file to be
+// wrapped. (If a file descriptor is given, it is closed when the
+// returned I/O object is closed, unless closefd is set to False.)
+//
+// mode is an optional string that specifies the mode in which the file
+// is opened. It defaults to 'r' which means open for reading in text
+// mode.  Other common values are 'w' for writing (truncating the file if
+// it already exists), 'x' for creating and writing to a new file, and
+// 'a' for appending (which on some Unix systems, means that all writes
+// append to the end of the file regardless of the current seek position).
+// In text mode, if encoding is not specified the encoding used is platform
+// dependent: locale.getencoding() is called to get the current locale encoding.
+// (For reading and writing raw bytes use binary mode and leave encoding
+// unspecified.) The available modes are:
+//
+// ========= ===============================================================
+// Character Meaning
+// --------- ---------------------------------------------------------------
+// 'r'       open for reading (default)
+// 'w'       open for writing, truncating the file first
+// 'x'       create a new file and open it for writing
+// 'a'       open for writing, appending to the end of the file if it exists
+// 'b'       binary mode
+// 't'       text mode (default)
+// '+'       open a disk file for updating (reading and writing)
+// ========= ===============================================================
+//
+// The default mode is 'rt' (open for reading text). For binary random
+// access, the mode 'w+b' opens and truncates the file to 0 bytes, while
+// 'r+b' opens the file without truncation. The 'x' mode implies 'w' and
+// raises an `FileExistsError` if the file already exists.
+//
+// Python distinguishes between files opened in binary and text modes,
+// even when the underlying operating system doesn't. Files opened in
+// binary mode (appending 'b' to the mode argument) return contents as
+// bytes objects without any decoding. In text mode (the default, or when
+// 't' is appended to the mode argument), the contents of the file are
+// returned as strings, the bytes having been first decoded using a
+// platform-dependent encoding or using the specified encoding if given.
+//
+// buffering is an optional integer used to set the buffering policy.
+// Pass 0 to switch buffering off (only allowed in binary mode), 1 to select
+// line buffering (only usable in text mode), and an integer > 1 to indicate
+// the size of a fixed-size chunk buffer.  When no buffering argument is
+// given, the default buffering policy works as follows:
+//
+//   - Binary files are buffered in fixed-size chunks; the size of the buffer
+//     is chosen using a heuristic trying to determine the underlying device's
+//     "block size" and falling back on `io.DEFAULT_BUFFER_SIZE`.
+//     On many systems, the buffer will typically be 4096 or 8192 bytes long.
+//
+//   - "Interactive" text files (files for which isatty() returns True)
+//     use line buffering.  Other text files use the policy described above
+//     for binary files.
+//
+// encoding is the name of the encoding used to decode or encode the
+// file. This should only be used in text mode. The default encoding is
+// platform dependent, but any encoding supported by Python can be
+// passed.  See the codecs module for the list of supported encodings.
+//
+// errors is an optional string that specifies how encoding errors are to
+// be handled---this argument should not be used in binary mode. Pass
+// 'strict' to raise a ValueError exception if there is an encoding error
+// (the default of None has the same effect), or pass 'ignore' to ignore
+// errors. (Note that ignoring encoding errors can lead to data loss.)
+// See the documentation for codecs.register or run 'help(codecs.Codec)'
+// for a list of the permitted encoding error strings.
+//
+// newline controls how universal newlines works (it only applies to text
+// mode). It can be None, ”, '\n', '\r', and '\r\n'.  It works as
+// follows:
+//
+//   - On input, if newline is None, universal newlines mode is
+//     enabled. Lines in the input can end in '\n', '\r', or '\r\n', and
+//     these are translated into '\n' before being returned to the
+//     caller. If it is ”, universal newline mode is enabled, but line
+//     endings are returned to the caller untranslated. If it has any of
+//     the other legal values, input lines are only terminated by the given
+//     string, and the line ending is returned to the caller untranslated.
+//
+//   - On output, if newline is None, any '\n' characters written are
+//     translated to the system default line separator, os.linesep. If
+//     newline is ” or '\n', no translation takes place. If newline is any
+//     of the other legal values, any '\n' characters written are translated
+//     to the given string.
+//
+// If closefd is False, the underlying file descriptor will be kept open
+// when the file is closed. This does not work when a file name is given
+// and must be True in that case.
+//
+// A custom opener can be used by passing a callable as *opener*. The
+// underlying file descriptor for the file object is then obtained by
+// calling *opener* with (*file*, *flags*). *opener* must return an open
+// file descriptor (passing os.open as *opener* results in functionality
+// similar to passing None).
+//
+// open() returns a file object whose type depends on the mode, and
+// through which the standard file operations such as reading and writing
+// are performed. When open() is used to open a file in a text mode ('w',
+// 'r', 'wt', 'rt', etc.), it returns a TextIOWrapper. When used to open
+// a file in a binary mode, the returned class varies: in read binary
+// mode, it returns a BufferedReader; in write binary and append binary
+// modes, it returns a BufferedWriter, and in read/write mode, it returns
+// a BufferedRandom.
+//
+// It is also possible to use a string or bytearray as a file for both
+// reading and writing. For strings StringIO can be used like a file
+// opened in a text mode, and for bytes a BytesIO can be used like a file
+// opened in a binary mode.
+//
+//go:linkname Open py.open
+func Open(file *py.Object, mode *py.Object, buffering *py.Object, encoding *py.Object, errors *py.Object, newline *py.Object, closefd *py.Object, opener *py.Object) *py.Object
diff --git a/py/std/llgo_autogen.lla b/py/std/llgo_autogen.lla
new file mode 100644
index 00000000..3767c27f
Binary files /dev/null and b/py/std/llgo_autogen.lla differ