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: New ChainMap from maps[1:].
docstr_tok: ["New","ChainMap","from","maps","[","1",":","]","."]
code: def parents(self):  # like Django's Context.pop()
      "New ChainMap from maps[1:]."
      return self.__class__(*self.maps[1:])
  
imports: import sys
label_desc: Use image node_id 13 for calling the ChainMap obj's underlying member method code with example usage: obj.parents() and returns: self