/**
  * Set RelationshipType value
  * @uses \Ews\EnumType\EwsXrmGraphRelationshipType::valueIsValid()
  * @uses \Ews\EnumType\EwsXrmGraphRelationshipType::getValidValues()
  * @throws \InvalidArgumentException
  * @param string $relationshipType
  * @return \Ews\StructType\EwsCreateXrmGraphRelationshipType
  */
 public function setRelationshipType($relationshipType = null)
 {
     // validation for constraint: enumeration
     if (!\Ews\EnumType\EwsXrmGraphRelationshipType::valueIsValid($relationshipType)) {
         throw new \InvalidArgumentException(sprintf('Value "%s" is invalid, please use one of: %s', $relationshipType, implode(', ', \Ews\EnumType\EwsXrmGraphRelationshipType::getValidValues())), __LINE__);
     }
     $this->RelationshipType = $relationshipType;
     return $this;
 }
 /**
  * Add element to array
  * @see AbstractStructArrayBase::add()
  * @throws \InvalidArgumentException
  * @uses \Ews\EnumType\EwsXrmGraphRelationshipType::valueIsValid()
  * @param string $item
  * @return \Ews\ArrayType\EwsArrayOfXrmGraphRelationshipType
  */
 public function add($item)
 {
     if (!\Ews\EnumType\EwsXrmGraphRelationshipType::valueIsValid($item)) {
         throw new \InvalidArgumentException(sprintf('Value "%s" is invalid, please use one of: %s', $item, implode(', ', \Ews\EnumType\EwsXrmGraphRelationshipType::getValidValues())), __LINE__);
     }
     return parent::add($item);
 }