code: def A2(self):
          
          if self.params['qop'] == 'auth' or not self.params['qop']:
              return self.request.method + ":" + self.request.uri
          elif self.params['qop'] == 'auth-int':
              #print "UNSUPPORTED 'qop' METHOD\n"
              return ":".join([self.request.method,
                               self.request.uri,
                               self.apply_checksum(self.request.body)])
          else:
              print "A2 GOT BAD VALUE FOR 'qop': %s\n" % self.params['qop']
docs: If the "qop" directive's value is "auth" or is unspecified, then A2 is:
              A2 = Method ":" digest-uri-value
          Else,
              A2 = Method ":" digest-uri-value ":" H(entity-body)