text: # -*- coding: utf-8 -*-
  # Copyright (c) 2015-2020, Exa Analytics Development Team
  # Distributed under the terms of the Apache License 2.0
  
  from exa import DataFrame
  import numpy as np
  #import pandas as pd
  
  class Gradient(DataFrame):
      """
      The gradient dataframe
      """
      # simple function that will have to be seen if it can have any other functions
      _index = 'gradient'
      _columns = ['Z', 'atom', 'fx', 'fy', 'fz', 'symbol', 'frame']
      _categories = {'frame': np.int64, 'atom': np.int64, 'symbol': str}
  