''' Q7: Given an input string x, return True if it is a palindrome.
>>> f('Hello')
False
>>> f('')
True
>>> f('A')
True
>>> f('dood')
True
>>> f('Dood')
False
>>> f('DooD')
True
>>> f('DoD')
True
>>> f('1234321')
True
'''

def f(x):
    # Your Code Here!
    pass

if __name__ == '__main__':
    import doctest
    doctest.testmod()