code: def addIdentifier(self,
                        identifier=None,
                        seed=None,
                        signer=None,
                        alias=None,
                        didMethodName=None):
          
  
          dm = self.didMethods.get(didMethodName)
          signer = signer or dm.newSigner(identifier=identifier, seed=seed)
          self.idsToSigners[signer.identifier] = signer
          if self.defaultId is None:
              # setting this signer as default signer to let use sign* methods
              # without explicit specification of signer
              self.defaultId = signer.identifier
          if alias:
              signer.alias = alias
          if signer.alias:
              self.aliasesToIds[signer.alias] = signer.identifier
          return signer.identifier, signer
docs: Adds signer to the wallet.
          Requires complete signer, identifier or seed.
  
          :param identifier: signer identifier or None to use random one
          :param seed: signer key seed or None to use random one
          :param signer: signer to add
          :param alias: a friendly readable name for the signer
          :param didMethodName: name of DID Method if not the default
          :return: