code: @Override
      public RelationshipFeed setUserRelationship(String userId, Relationship relationship) throws InstagramException {
          Preconditions.checkEmptyString(userId, USER_ID_CANNOT_BE_NULL_OR_EMPTY);
          Preconditions.checkNotNull(relationship, "relationship cannot be null.");
  
          String apiMethod = format(Methods.USERS_ID_RELATIONSHIP, userId);
          Map<String, String> params = new HashMap<String, String>();
  
          params.put(QueryParam.ACTION, relationship.toString());
  
          return createInstagramObject(Verbs.POST, RelationshipFeed.class, apiMethod, params);
  
      }
docs: /* (non-Javadoc)
  @see org.jinstagram.InstagramClient#setUserRelationship(java.lang.String, org.jinstagram.model.Relationship)