def add(self, abspath_or_winfile, enable_verbose=True):
        """Add absolute path or WinFile to FileCollection.
        """
        if isinstance(abspath_or_winfile, str): # abspath
            if abspath_or_winfile in self.files:
                if enable_verbose:
                    print("'%s' already in this collections" % 
                          abspath_or_winfile)
            else:
                self.files.setdefault(abspath_or_winfile, WinFile(abspath_or_winfile))
        elif isinstance(abspath_or_winfile, WinFile): # WinFile
            if abspath_or_winfile.abspath in self.files:
                if enable_verbose:
                    print("'%s' already in this collections" % 
                          abspath_or_winfile)
            else:
                self.files.setdefault(abspath_or_winfile.abspath, abspath_or_winfile)
        else:
            raise TypeError
Add absolute path or WinFile to FileCollection.