input: Write a function to modify the given Python code so that it raises an exception if the input value is not 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
  try:
      square_root('4')
  except TypeError:
      assert True
  else:
      assert False
  try:
      square_root(4.5)
  except TypeError:
      assert True
  else:
      assert False
output: def square_root(x):
      if not isinstance(x, int):
          raise TypeError('Input must be an integer')
      return x**0.5