compare the two versions of 'endswith'.
Either  both of them should throw TypeErorr or both 
should return boolean value. 


>>> 'abc'.endswith( ('abc',None))

True

>>> 'abc'.endswith( ('abc',None),4,3)

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

TypeError: expected a character buffer object