code: def setPendingKeyExchange(self, sequence, ourBaseKey, ourRatchetKey, ourIdentityKey):
          
          structure = self.sessionStructure.PendingKeyExchange()
          structure.sequence = sequence
          structure.localBaseKey = ourBaseKey.getPublicKey().serialize()
          structure.localBaseKeyPrivate = ourBaseKey.getPrivateKey().serialize()
          structure.localRatchetKey = ourRatchetKey.getPublicKey().serialize()
          structure.localRatchetKeyPrivate = ourRatchetKey.getPrivateKey().serialize()
          structure.localIdentityKey = ourIdentityKey.getPublicKey().serialize()
          structure.localIdentityKeyPrivate = ourIdentityKey.getPrivateKey().serialize()
  
          self.sessionStructure.pendingKeyExchange.MergeFrom(structure)
docs: :type sequence: int
          :type ourBaseKey: ECKeyPair
          :type ourRatchetKey: ECKeyPair
          :type  ourIdentityKey: IdentityKeyPair