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

def get_string(self):

    if self.is_null():
        return None
    if ((self.ver_major == self.latest_ver_major) and (self.ver_minor == self.latest_ver_minor)):
        return 'latest'
    return ('%s.%s' % (self.ver_major, self.ver_minor))
