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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 Override(self, overrides):
 """ Produce a modified environment whose variables are overridden by the overrides dictionaries. "overrides" is a dictionary that will override the variables of this environment. This function is much more efficient than Clone() or creating a new Environment because it doesn't copy the construction environment dictionary, it just wraps the underlying construction environment, and doesn't even create a wrapper object if there are no overrides. """

        if not overrides: return self
        o = copy_non_reserved_keywords(overrides)
        if not o: return self
        overrides = {}
        merges = None
        for key, value in o.items():
            if key == 'parse_flags':
                merges = value
            else:
                overrides[key] = SCons.Subst.scons_subst_once(value, self, key)
        env = OverrideEnvironment(self, overrides)
        if merges: env.MergeFlags(merges)
        return env