input: Write a function to modify the given code so that it raises a TypeError exception if the input value is not an integer. The function should retain its original functionality if the input is an integer.
  def square_root(x):
      if not isinstance(x, int):
          raise TypeError('Input must be an integer')
      return x**0.5
  assert square_root(4)==2.0
  assert square_root(9)==3.0
  assert square_root('4')==TypeError
  assert square_root(4.0)==TypeError
  assert square_root(None)==TypeError
output: def square_root(x):
      if not isinstance(x, int):
          raise TypeError('Input must be an integer')
      return x**0.5