code: def _energy_distance_imp(x, y, exponent=1):
      
      x = _transform_to_2d(x)
      y = _transform_to_2d(y)
  
      _check_valid_energy_exponent(exponent)
  
      distance_xx = distances.pairwise_distances(x, exponent=exponent)
      distance_yy = distances.pairwise_distances(y, exponent=exponent)
      distance_xy = distances.pairwise_distances(x, y, exponent=exponent)
  
      return _energy_distance_from_distance_matrices(distance_xx=distance_xx,
                                                     distance_yy=distance_yy,
                                                     distance_xy=distance_xy)
docs: Real implementation of :func:`energy_distance`.
  
      This function is used to make parameter ``exponent`` keyword-only in
      Python 2.