function findName( scope, expected ) {
	var keys = objectKeys( scope );
	var key;
	var i;
	for ( i = 0; i < keys.length; i++ ) {
		key = keys[ i ];
		if (
			!contains( SCOPE_DEFAULTS, key ) &&
			!compareValues( scope[ key ], expected )
		) {
			return key;
		}
	}
	return '?';
}
Searches for variable in scope matching the expected value.

@private
@param {Object} scope - VM scope
@param {any} expected - expected value to search for
@returns {string} variable name or `?` if no match found