code: def _calc_distortion(self):
          
          m = self._X.shape[0]
          self.distortion = 1/m * sum(
              linalg.norm(self._X[i, :] - self.centroids[self.clusters[i]])**2 for i in range(m)
          )
          return self.distortion
docs: Calculates the distortion value of the current clusters