code: def _add_attribute_values(self, value, att_mappings, indices):
          
          for i in indices:
              att_mappings[i].append(value)
docs: Add an attribute value to the given vertices.
  
          :param int value: Attribute value.
          :param dict att_mappings: Dictionary of mappings between vertices and enumerated attributes.
          :param list indices: Indices of the vertices.