input: Write a python function to plot a histogram using matplotlib.
  assert plot_histogram([1,2,3,4,5,4,3,2,1], [1,2,3,4,5,4,3,2,1]) == None
  assert plot_histogram([1,2,2,3,3,3,4,4,4,4], [2,3,4,5,6,7,8,9,10,11]) == None
output: import matplotlib.pyplot as plt
  
  def plot_histogram(data, bins):
      plt.hist(data, bins=bins)
      plt.xlabel('Data')
      plt.ylabel('Frequency')
      plt.title('Histogram')
      plt.show()