input: Write a function that modifies the provided Python code to raise an exception if the input value is not an integer. The original function calculates the square root of the input. If the input is not an integer, the function should raise a TypeError with the message 'Input must be an integer'. Once modified, the function should return the square root of the input if it 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
  try:
      square_root('a')
  except TypeError as e:
      assert str(e) == 'Input must be an integer'
  try:
      square_root(4.0)
  except TypeError as e:
      assert str(e) == 'Input must be an integer'
  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