code: function toSource$3(func) {
  	  if (func != null) {
  	    try {
  	      return funcToString$4.call(func);
  	    } catch (e) {}
  	    try {
  	      return (func + '');
  	    } catch (e) {}
  	  }
  	  return '';
  	}
docs: Converts `func` to its source code.
  
  @private
  @param {Function} func The function to process.
  @returns {string} Returns the source code.