code: def gradient_angle(self):
          
          if self.type != MSO_FILL.GRADIENT:
              raise TypeError('Fill is not of type MSO_FILL_TYPE.GRADIENT')
          return self._fill.gradient_angle
docs: Angle in float degrees of line of a linear gradient.
  
          Read/Write. May be |None|, indicating the angle should be inherited
          from the style hierarchy. An angle of 0.0 corresponds to
          a left-to-right gradient. Increasing angles represent
          counter-clockwise rotation of the line, for example 90.0 represents
          a bottom-to-top gradient. Raises |TypeError| when the fill type is
          not MSO_FILL_TYPE.GRADIENT. Raises |ValueError| for a non-linear
          gradient (e.g. a radial gradient).