code: def trim_field_key(document, field_key):
      
      trimming = True
      left_over_key_values = []
      current_key = field_key
      while trimming and current_key:
          if hasattr(document, current_key):
              trimming = False
          else:
              key_array = current_key.split("_")
              left_over_key_values.append(key_array.pop())
              current_key = u"_".join(key_array)
  
      left_over_key_values.reverse()
      return current_key, left_over_key_values
docs: Returns the smallest delimited version of field_key that
      is an attribute on document.
  
      return (key, left_over_array)