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 and return an item pair from maps[0]. Raise KeyError is maps[0]
  is empty.
docstr_tok: ["Remove","and","return","an","item","pair","from","maps","[","0","]",".","Raise","KeyError","is","maps","[","0","]","is","empty","."]
code: def popitem(self):
      """
      Remove and return an item pair from maps[0]. Raise KeyError is maps[0]
      is empty.
      """
      try:
          return self.maps[0].popitem()
      except KeyError:
          raise KeyError("No keys found in the first mapping.")
  
imports: import sys
label_desc: Use image node_id 16 for calling the ChainMap obj's underlying member method code with example usage: obj.popitem() and returns: self