docs: def linestyle(self, linestyle=None):
          """Returns or sets (if a value is provided) the series' linestyle. See\
          `OmniCanvas docs <https://omnicanvas.readthedocs.io/en/latest/api/graph\
          ics.html#omnicanvas.graphics.ShapeGraphic.line_style>`_ for acceptable
          values.
  
          :param str linestyle: If given, the series' linestyle will be set to\
          this.
          :rtype: ``str``"""
  
          if linestyle is None:
              return self._linestyle
          else:
              if not isinstance(linestyle, str):
                  raise TypeError(
                   "linestyle must be str, not '%s'" % str(linestyle)
                  )
              self._linestyle = linestyle