code: def main_color(self):
          
          if self.kind is None:
              return DEFAULT_COLOR
          elif self.kind == 'face':
              colors = self.face_colors
          elif self.kind == 'vertex':
              colors = self.vertex_colors
          else:
              raise ValueError('color kind incorrect!')
  
          # find the unique colors
          unique, inverse = grouping.unique_rows(colors)
          # the most commonly occurring color, or mode
          # this will be an index of inverse, not colors
          mode_index = np.bincount(inverse).argmax()
          color = colors[unique[mode_index]]
  
          return color
docs: What is the most commonly occurring color.
  
          Returns
          ------------
          color: (4,) uint8, most common color