Returns object from methods for chaining purpose

framework/base/Model.php

@@ -686,6 +686,7 @@ public function getAttributes($names = null, $except = [])
      * @param array $values attribute values (name => value) to be assigned to the model.
      * @param boolean $safeOnly whether the assignments should only be done to the safe attributes.
      * A safe attribute is one that is associated with a validation rule in the current [[scenario]].
+     * @return $this
      * @see safeAttributes()
      * @see attributes()
      */
@@ -701,6 +702,8 @@ public function setAttributes($values, $safeOnly = true)
                 }
             }
         }
+
+        return $this;
     }
 
     /**

framework/db/ActiveRecordInterface.php

@@ -47,6 +47,7 @@ public function getAttribute($name);
      * Sets the named attribute value.
      * @param string $name the attribute name.
      * @param mixed $value the attribute value.
+     * @return $this
      * @see hasAttribute()
      */
     public function setAttribute($name, $value);

framework/db/BaseActiveRecord.php

@@ -459,13 +459,16 @@ protected function setAttributeInternal($name, $value, $check = true)
      * @param string $name the attribute name
      * @param mixed $value the attribute value.
      * @param boolean $throw Set to false to not throw an exception (used internally).
+     * @return $this
      * @see hasAttribute()
      */
     public function setAttribute($name, $value)
     {
         if (!$this->setAttributeInternal($name, $value)) {
             throw new InvalidParamException(get_class($this) . ' has no attribute named "' . $name . '".');
         }
+
+        return $this;
     }
 
 
@@ -483,10 +486,13 @@ public function getOldAttributes()
      * All existing old attribute values will be discarded.
      * @param array|null $values old attribute values to be set.
      * If set to `null` this record is considered to be [[isNewRecord|new]].
+     * @return $this
      */
     public function setOldAttributes($values)
     {
         $this->_oldAttributes = $values;
+
+        return $this;
     }
 
     /**
@@ -507,6 +513,7 @@ public function getOldAttribute($name)
      * Sets the old value of the named attribute.
      * @param string $name the attribute name
      * @param mixed $value the old attribute value.
+     * @return $this
      * @throws InvalidParamException if the named attribute does not exist.
      * @see hasAttribute()
      */
@@ -517,6 +524,8 @@ public function setOldAttribute($name, $value)
         } else {
             throw new InvalidParamException(get_class($this) . ' has no attribute named "' . $name . '".');
         }
+
+        return $this;
     }
 
     /**