text: """
      Plotting utility module
      =======================
  
      Work in progress...
  
  """
  import matplotlib.pyplot as plt
  
  
  def std_plot(x, mean, std, ax=None, **kwargs):
      """Plot a mean and a standard deviation time series.
  
      Parameters
      ----------
      x: ~numpy.ndarray
          1D array of the x-axis values (usually time)
      mean: ~numpy.ndarray
          1D array of mean values to represent, should have the same shape as x.
  
      std: ~numpy.ndarray
          1D array of standard deviation values to represent, should have the same shape as mean.
      ax: None or ~matplotlib.axes.Axes
          A `matplotlib`_ axes instance to plot the values. If None, create one.
      kwargs: dict
          Keyword arguments to be given to the plot routine.
  
      Returns
      -------
      ~matplotlib.axes.Axes
          The axes instance on which the values where plotted.
  
  
      .. _matplotlib: https://matplotlib.org/
      """
  
      if ax is None:
          fig = plt.figure()
          ax = fig.gca()
  
      ax.fill_between(x, mean - std, mean + std, **kwargs)
  
      return ax
  