This reads and returns one entire line. The newline at the end of
        line is returned as part of the string, unless the file ends without a
        newline. An empty string is returned if EOF is encountered immediately.
        This looks for a newline as a CR/LF pair (\\r\\n) even on UNIX because
        this is what the pseudotty device returns. So contrary to what you may
        expect you will receive newlines as \\r\\n.

        If the size argument is 0 then an empty string is returned. In all
        other cases the size argument is ignored, which is not standard
        behavior for a file-like object.

def readline(self, size=-1):
        '''This reads and returns one entire line. The newline at the end of
        line is returned as part of the string, unless the file ends without a
        newline. An empty string is returned if EOF is encountered immediately.
        This looks for a newline as a CR/LF pair (\\r\\n) even on UNIX because
        this is what the pseudotty device returns. So contrary to what you may
        expect you will receive newlines as \\r\\n.

        If the size argument is 0 then an empty string is returned. In all
        other cases the size argument is ignored, which is not standard
        behavior for a file-like object. '''

        if size == 0:
            return self.string_type()
        # delimiter default is EOF
        index = self.expect([self.crlf, self.delimiter])
        if index == 0:
            return self.before + self.crlf
        else:
            return self.before