code: def setup_data(self):
          
          data = self.data
          if len(data) == 0:
              return type(data)()
  
          data = self.geom.setup_data(data)
  
          check_required_aesthetics(
              self.geom.REQUIRED_AES,
              set(data.columns) | set(self.geom.aes_params),
              self.geom.__class__.__name__)
  
          self.data = data
docs: Prepare/modify data for plotting