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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 check(self):
 """Check if a file is changed """

        for (path, handler) in self.handlers.items():
            current_signature = self.signatures[path]
            new_signature = self.get_path_signature(path)
            if new_signature != current_signature:
                self.signatures[path] = new_signature
                handler.on_change(Event(path))