docs: def serialize(
              self,
              value,  # type: Any
              state  # type: _ProcessorState
      ):
          # type: (...) -> ET.Element
          """
          Serialize the value into a new element object and return the element.
  
          If the omit_empty option was specified and the value is falsey, then this will return None.
          """
          # For primitive values, this is only called when the value is part of an array,
          # in which case we do not need to check for missing or omitted values.
          start_element, end_element = _element_path_create_new(self.element_path)
          self._serialize(end_element, value, state)
          return start_element