input: Write a function to create an identity matrix of a given size using numpy.
  assert (create_identity_matrix(3) == np.identity(3)).all()
  assert (create_identity_matrix(5) == np.identity(5)).all()
  assert (create_identity_matrix(1) == np.identity(1)).all()
output: import numpy as np
  
  def create_identity_matrix(size):
      return np.identity(size)