docs: def set_element_dt(self, el_name, dt, tz=None, el_idx=0):
          """Set the text of the selected element to an ISO8601 formatted datetime.
  
          Args:
            el_name : str
              Name of element to update.
  
            dt : datetime.datetime
              Date and time to set
  
            tz : datetime.tzinfo
              Timezone to set
  
              - Without a timezone, other contextual information is required in order to
                determine the exact represented time.
              - If dt has timezone: The ``tz`` parameter is ignored.
              - If dt is naive (without timezone): The timezone is set to ``tz``.
              - ``tz=None``: Prevent naive dt from being set to a timezone. Without a
                timezone, other contextual information is required in order to determine
                the exact represented time.
              - ``tz=d1_common.date_time.UTC()``: Set naive dt to UTC.
  
            el_idx : int
              Index of element to use in the event that there are multiple sibling
              elements with the same name.
  
          """
          dt = d1_common.date_time.cast_naive_datetime_to_tz(dt, tz)
          self.get_element_by_name(el_name, el_idx).text = dt.isoformat()