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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 _merge_pool_kwargs(self, override):
 """ Merge a dictionary of override values for self.connection_pool_kw. This does not modify self.connection_pool_kw and returns a new dict. Any keys in the override dictionary with a value of ``None`` are removed from the merged dictionary. """

        base_pool_kwargs = self.connection_pool_kw.copy()
        if override:
            for key, value in override.items():
                if value is None:
                    try:
                        del base_pool_kwargs[key]
                    except KeyError:
                        pass
                else:
                    base_pool_kwargs[key] = value
        return base_pool_kwargs