function toSource(func) {
			if (func != null) {
				try {
					return funcToString.call(func);
				} catch (e) {}
				try {
					return (func + '');
				} catch (e) {}
			}
			return '';
		}
Converts `func` to its source code.

@private
@param {Function} func The function to process.
@returns {string} Returns the source code.