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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 processed_file(self, new_text, filename, old_text=None, write=False, encoding=None):
 """ Called when a file has been refactored and there may be changes. """

        self.files.append(filename)
        if old_text is None:
            old_text = self._read_python_source(filename)[0]
            if old_text is None:
                return
        equal = old_text == new_text
        self.print_output(old_text, new_text, filename, equal)
        if equal:
            self.log_debug("No changes to %s", filename)
            if not self.write_unchanged_files:
                return
        if write:
            self.write_file(new_text, filename, old_text, encoding)
        else:
            self.log_debug("Not writing changes to %s", filename)