question: make the given type expression into an optional type expression , if possible . concode_field_sep Node root concode_elem_sep long serialVersionUID concode_elem_sep String sourceName concode_field_sep boolean isOptionalArg concode_elem_sep boolean isVarArgs concode_elem_sep int hashCode concode_elem_sep boolean equals concode_elem_sep Node getRoot concode_elem_sep JSType evaluate
target: JSTypeExpression function ( JSTypeExpression arg0 ) { if ( arg0 . isOptionalArg ( ) || arg0 . isVarArgs ( ) ) { return arg0 ; } else { return new JSTypeExpression ( new Node ( Token . EQUALS , arg0 . root ) , arg0 . sourceName ) ; } }