class_docstr: A ChainMap groups multiple dicts (or other mappings) together
  to create a single, updatable view.
  
  The underlying mappings are stored in a list.  That list is public and can
  be accessed / updated using the *maps* attribute.  There is no other state.
  
  Lookups search the underlying mappings successively until a key is found.
  In contrast, writes, updates, and deletions only operate on the first
  mapping.
docstr: Remove *key* from maps[0] and return its value. Raise KeyError if
  *key* not in maps[0].
docstr_tok: ["Remove","*","key","*","from","maps","[","0","]","and","return","its","value",".","Raise","KeyError","if","*","key","*","not","in","maps","[","0","]","."]
code: def pop(self, key, *args):
      """
      Remove *key* from maps[0] and return its value. Raise KeyError if
      *key* not in maps[0].
      """
      try:
          return self.maps[0].pop(key, *args)
      except KeyError:
          raise KeyError(
              "Key not found in the first mapping: {!r}".format(key)
          )
  
imports: import sys
label_desc: Use image node_id 17 for calling the ChainMap obj's underlying member method code with example usage: obj.pop(key) and returns: self