code: def ytickangle(self, angle, index=1):
          
          self.layout['yaxis' + str(index)]['tickangle'] = angle
          return self
docs: Set the angle of the y-axis tick labels.
  
          Parameters
          ----------
          value : int
              Angle in degrees
          index : int, optional
              Y-axis index
  
          Returns
          -------
          Chart