input: Write a function to modify the given Python code so that it raises a `TypeError` exception if the input value is not an integer. If the input value is an integer, return its square root.
  
  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('a')
  except TypeError:
      pass
  else:
      assert False, "Expected TypeError but did not raise"
  assert square_root(16) == 4.0
  
output: def square_root(x):
      if not isinstance(x, int):
          raise TypeError('Input must be an integer')
      return x**0.5