public function offsetUnset($offset)
    {
        unset($this->map[$offset]);
        $this->origin = $this->map->keys();
        return $this;
    }
public function offsetUnset($offset)
    {
        unset($this->map[$offset]);
        $this->origin = $this->map->keys();
        return $this;
    }
public function offsetUnset ( $ offset ) { unset ( $ this -> map [ $ offset ] ) ; $ this -> origin = $ this -> map -> keys ( ) ; return $ this ; }
ArrayAccess. Deletes the given key offset.

@param $offset
@return $this;
ArrayAccess . Deletes the given key offset .