input: Write a python function to plot a bar chart given lists of x and y values using matplotlib.
  assert plot_bar_chart([4, 6, 3, 7, 2], [0, 2, 3, 4, 5])==None
  assert plot_bar_chart([1, 2, 3], [1, 4, 9])==None
  assert plot_bar_chart([10, 20, 30], [10, 20, 30])==None
output: def plot_bar_chart(x, y):
      import matplotlib.pyplot as plt
      
      plt.bar(x, y)
      plt.xlabel('X values')
      plt.ylabel('Y values')
      plt.title('Bar Chart')
      plt.show()