'Version string representation.
Converts object to string representation which if used to create
an APIVersion object results in the same version.'

def get_string(self):

    if self.is_null():
        raise ValueError(_('Null    APIVersion    cannot    be    converted    to    string.'))
    elif self.is_latest():
        return ('%s.%s' % (self.ver_major, 'latest'))
    return ('%s.%s' % (self.ver_major, self.ver_minor))
