A string naming the method to invoke.
can-invoke-p is used to check whether an Objective-C instance and class method can be invoked (is defined) for a given class. If class-or-object-pointer is a string, then it must name an Objective-C class and the class method named method in that class is checked. Otherwise class-or-object-pointer should be a foreign pointer to an Objective-C object or class and the appropriate instance or class method named method is checked. The value of method should be a concatenation of the message name and its argument names, including the colons, for example
LispWorks Objective-C and Cocoa Interface User Guide and Reference Manual - 15 Feb 2015