input: Write a python function to plot a bar graph using matplotlib with given data.
  assert plot_bar_graph([1, 2, 3, 6, 5, 4, 7])==None
  assert plot_bar_graph([10, 20, 30, 25, 15, 10])==None
  assert plot_bar_graph([7, 8, 5, 6, 9])==None
output: def plot_bar_graph(data):
      import matplotlib.pyplot as plt
      
      plt.bar(range(len(data)), data)
      plt.xlabel('Index')
      plt.ylabel('Value')
      plt.title('Bar Graph')
      plt.show()