class_docstr: Class for the copy builtin message function.
  
  See Also
  --------
  copy_u
class_docstr_tok: ["Class","for","the","copy","builtin","message","function",".","See","Also","--","--","--","--","copy_u"]
code: def __init__(self, target, in_field, out_field):
      self.target = target
      self.in_field = in_field
      self.out_field = out_field
  
file_path: dgl/python/dgl/function/message.py
imports: from __future__ import absolute_import
  import sys
  from itertools import product
  from .base import BuiltinFunction, TargetCode
label_desc: Use image node_id 1 to create a new CopyMessageFunction object from inherited base classes: MessageFunction with example: obj = CopyMessageFunction(target, in_field, out_field)