Nurdok

>>> seq = ['abc', 'def', 'g', 'hi']
... [y for x in seq if len(seq) > 1 for y in x if y != 'e']
['a', 'b', 'c', 'd', 'f', 'g', 'h', 'i']

Nurdok

class SingletonType(type):

    def __call__(cls, *args, **kwargs):
        try:
            return cls.__instance
        except AttributeError:
            cls.__instance = super(SingletonType, cls).__call__(*args, **kwargs)
            return cls.__instance