docs: def to_slice(arr):
      """Test whether `arr` is an integer array that can be replaced by a slice
  
      Parameters
      ----------
      arr: numpy.array
          Numpy integer array
  
      Returns
      -------
      slice or None
          If `arr` could be converted to an array, this is returned, otherwise
          `None` is returned
  
      See Also
      --------
      get_index_from_coord"""
      if isinstance(arr, slice):
          return arr
      if len(arr) == 1:
          return slice(arr[0], arr[0] + 1)
      step = np.unique(arr[1:] - arr[:-1])
      if len(step) == 1:
          return slice(arr[0], arr[-1] + step[0], step[0])