input: Write a function to check if the provided input to the square_root function is an integer. If it is not an integer, raise a TypeError with the message 'Input must be an integer'. Otherwise, return the square root of the input.
  
  ### Input:
  def square_root(x):
      return x**0.5
  
  ### Output:
  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') # should raise TypeError
output: def square_root(x):
      if not isinstance(x, int):
          raise TypeError('Input must be an integer')
      return x**0.5