docs: def set_decade_lims(axis=None,direction=None):
    r'''
  Set limits the the floor/ceil values in terms of decades.
  
  :options:
  
    **axis** ([``plt.gca()``] | ...)
      Specify the axis to which to apply the limits.
  
    **direction** ([``None``] | ``'x'`` | ``'y'``)
      Limit the application to a certain direction (default: both).
    '''
  
    # get current axis
    if axis is None:
      axis = plt.gca()
  
    # x-axis
    if direction is None or direction == 'x':
      # - get current limits
      MIN,MAX = axis.get_xlim()
      # - floor/ceil to full decades
      MIN = 10 ** ( np.floor(np.log10(MIN)) )
      MAX = 10 ** ( np.ceil (np.log10(MAX)) )
      # - apply
      axis.set_xlim([MIN,MAX])
  
    # y-axis
    if direction is None or direction == 'y':
      # - get current limits
      MIN,MAX = axis.get_ylim()
      # - floor/ceil to full decades
      MIN = 10 ** ( np.floor(np.log10(MIN)) )
      MAX = 10 ** ( np.ceil (np.log10(MAX)) )
      # - apply
      axis.set_ylim([MIN,MAX])