code: def _line_spacing(spacing_line, spacing_lineRule):
          
          if spacing_line is None:
              return None
          if spacing_lineRule == WD_LINE_SPACING.MULTIPLE:
              return spacing_line / Pt(12)
          return spacing_line
docs: Return the line spacing value calculated from the combination of
          *spacing_line* and *spacing_lineRule*. Returns a |float| number of
          lines when *spacing_lineRule* is ``WD_LINE_SPACING.MULTIPLE``,
          otherwise a |Length| object of absolute line height is returned.
          Returns |None| when *spacing_line* is |None|.