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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 _valid_file(self, base, name):
 """Return whether a file can be searched."""


        valid = False
        fullpath = os.path.join(base, name)
        if self.file_check is not None and self.compare_file(fullpath[self._base_len:] if self.file_pathname else name):
            valid = True
        if valid and (not self.show_hidden and util.is_hidden(fullpath)):
            valid = False
        return self.on_validate_file(base, name) if valid else valid