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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 _have(self, name=None):
 """Check if a configure flag is set. If called without argument, it returns all HAVE_* items. Example: """

        if name is None:
            return (
                (k, v) for k, v  in self.env.items()
                if k.startswith('HAVE_')
            )
        return self.env.get('HAVE_' + self.env_key(name)) == True