A string naming the method to invoke.
is used to check whether an Objective-C instance and class method can be invoked (is defined) for a given class. If
is a string, then it must name an Objective-C class and the class method named
in that class is checked. Otherwise
should be a foreign pointer to an Objective-C object or class and the appropriate instance or class method named
is checked. The value of
should be a concatenation of the message name and its argument names, including the colons, for example