input: Write a python function to plot a pie chart for given items and their frequencies using matplotlib.
  assert plot_pie_chart(['Pen', 'Pencil', 'Eraser'], [4, 9, 3]) is None
  assert plot_pie_chart(['Apple', 'Banana', 'Cherry'], [10, 15, 5]) is None
  assert plot_pie_chart(['Cat', 'Dog', 'Bird'], [8, 6, 2]) is None
output: def plot_pie_chart(items, frequencies):
      import matplotlib.pyplot as plt
      
      plt.figure(figsize=(8,8))
      plt.pie(frequencies, labels=items, autopct='%1.1f%%', startangle=140)
      plt.axis('equal')  # Equal aspect ratio ensures that pie is drawn as a circle.
      plt.show()