Private instance variables

[mpd]

def __init__(self, first, last):
        self._first = first
        self._last = last
        self.e = self._f + self._l +'@gmail.com'

the first time self._f and self._l are used, they are being read. But they have never been defined so you get an Attributeerror

If you remove the last line from the __init__ method, it should work.