Internal WHERE IN

@used-by WhereIn()
@used-by orWhereIn()
@used-by whereNotIn()
@used-by orWhereNotIn()

@param string  $key    The field to search
@param array   $values The values searched on
@param boolean $not    If the statement would be IN or NOT IN
@param string  $type
@param boolean $escape

@return BaseBuilder