code: func (kp *Keypairs) Select(orgID *identity.ID, t primitive.KeyType) (*ClaimedKeyPair, error) {
  	if orgID == nil {
  		return nil, errors.New("Invalid OrgID Provided to select keypairs")
  	}
  
  	possible, ok := kp.keypairs[*orgID]
  	if !ok {
  		return nil, ErrMissingKeysForOrg
  	}
  
  	for _, k := range possible {
  		if k.PublicKey.Body.KeyType == t && !k.Revoked() {
  			return &k, nil
  		}
  	}
  
  	return nil, ErrMissingValidKeypair
  }
docs: // Select returns a keypair for the given type inside the specified
  // organization. If a valid key (non-revoked) cannot be found an error is
  // returned.