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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 visitParam_def(self, ctx:SystemRDLParser.Param_defContext):
 """ Parameter Definition block """

        self.compiler.namespace.enter_scope()

        param_defs = []
        for elem in ctx.getTypedRuleContexts(SystemRDLParser.Param_def_elemContext):
            param_def = self.visit(elem)
            param_defs.append(param_def)

        self.compiler.namespace.exit_scope()
        return param_defs