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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 add_key(self, key, first=False):
 """Adds the given key to this row. :param key: Key to be added to this row. :param first: BOolean flag that indicates if key is added at the beginning or at the end. """

        if first:
            self.keys = [key] + self.keys
        else:
            self.keys.append(key)
        if isinstance(key, VSpaceKey):
            self.space = key