text: """
  ================================================================
  Demo of the histogram function's different ``histtype`` settings
  ================================================================
  
  * Histogram with step curve that has a color fill.
  * Histogram with step curve with no fill.
  * Histogram with custom and unequal bin widths.
  * Two histograms with stacked bars.
  
  Selecting different bin counts and sizes can significantly affect the
  shape of a histogram. The Astropy docs have a great section on how to
  select these parameters:
  http://docs.astropy.org/en/stable/visualization/histogram.html
  """
  
  import numpy as np
  import matplotlib.pyplot as plt
  
  np.random.seed(19680801)
  
  mu_x = 200
  sigma_x = 25
  x = np.random.normal(mu_x, sigma_x, size=100)
  
  mu_w = 200
  sigma_w = 10
  w = np.random.normal(mu_w, sigma_w, size=100)
  
  fig, axs = plt.subplots(nrows=2, ncols=2)
  
  axs[0, 0].hist(x, 20, density=True, histtype='stepfilled', facecolor='g',
                 alpha=0.75)
  axs[0, 0].set_title('stepfilled')
  
  axs[0, 1].hist(x, 20, density=True, histtype='step', facecolor='g',
                 alpha=0.75)
  axs[0, 1].set_title('step')
  
  axs[1, 0].hist(x, density=True, histtype='barstacked', rwidth=0.8)
  axs[1, 0].hist(w, density=True, histtype='barstacked', rwidth=0.8)
  axs[1, 0].set_title('barstacked')
  
  # Create a histogram by providing the bin edges (unequally spaced).
  bins = [100, 150, 180, 195, 205, 220, 250, 300]
  axs[1, 1].hist(x, bins, density=True, histtype='bar', rwidth=0.8)
  axs[1, 1].set_title('bar, unequal bins')
  
  fig.tight_layout()
  plt.show()
  