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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _generator_file(self):
 """Generator for `self.filetype` of 'file'"""

        for path in self.paths:
            if os.path.isfile(path):
                if isvalid(path, self.access, self.extensions,
                           minsize=self.minsize):
                    yield os.path.abspath(path)
            elif os.path.isdir(path):
                for root, _, fnames in self._walker(path):
                    yield from self._generator_rebase(fnames, root)