class_docstr: Abstraction for the state of the CFG walk for type inference.
  
  This is a value type. Only implements the strictly necessary operators.
  
  Attributes:
    types: Dict[qual_names.QN, Set[Type]], mapping symbols to the set of
      possible types.
class_docstr_tok: ["Abstraction","for","the","state","of","the","CFG","walk","for","type","inference",".","This","is","a","value","type",".","Only","implements","the","strictly","necessary","operators",".","Attributes",":","types",":","Dict","[","qual_names.QN",",","Set","[","Type","]","]",",","mapping","symbols","to","the","set","of","possible","types","."]
code: def __init__(self, init_from=None):
      if init_from:
          assert isinstance(init_from, _TypeMap)
          self.types = {
              s: set(other_types)
              for s, other_types in init_from.types.items()
          }
      else:
          self.types = {}
  
imports: import itertools
  from typing import Any, Callable, Dict, Set
  import gast
  from tensorflow.python.autograph.pyct import anno
  from tensorflow.python.autograph.pyct import cfg
  from tensorflow.python.autograph.pyct import qual_names
  from tensorflow.python.autograph.pyct import transformer
  from tensorflow.python.autograph.pyct.static_analysis import activity
  from tensorflow.python.autograph.pyct.static_analysis import annos
label_desc: Use image node_id 1 to create a new _TypeMap object from inherited base classes: object with example: obj = _TypeMap(init_from)