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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 iter_items(cls, repo, common_path=None, remote=None):
 """Iterate remote references, and if given, constrain them to the given remote"""

        common_path = common_path or cls._common_path_default
        if remote is not None:
            common_path = join_path(common_path, str(remote))
        # END handle remote constraint
        return super(RemoteReference, cls).iter_items(repo, common_path)