docstr: Iterate squares of each value.
code: def __iter__(self):
      """Iterate squares of each value."""
      for i in self.values:
          yield i**2
  
imports: import enum
  from io import StringIO
  from ._functions_to_import import function_to_be_imported
label_desc: Use image node_id 2 for calling the CustomIter obj's underlying member method code with example usage: obj.__iter__() without return types