public function get_mapping_metakey( $attribute ) {
		$mapping = $this->get_mapping();

		return isset( $mapping[ $attribute ] ) ? $mapping[ $attribute ] : null;
	}
public function get_mapping_metakey( $attribute ) {
		$mapping = $this->get_mapping();

		return isset( $mapping[ $attribute ] ) ? $mapping[ $attribute ] : null;
	}
public function get_mapping_metakey ( $ attribute ) { $ mapping = $ this -> get_mapping ( ) ; return isset ( $ mapping [ $ attribute ] ) ? $ mapping [ $ attribute ] : null ; }
Get the mapping metakey by special attribute.

@param  string $attribute The attribute key to get metakey.
@return string|null
Get the mapping metakey by special attribute .