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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 _nacm_default_deny_stmt(self, stmt: Statement, sctx: SchemaContext) -> None: """Set NACM default access."""

        if not hasattr(self, 'default_deny'):
            return
        if stmt.keyword == "default-deny-all":
            self.default_deny = DefaultDeny.all
        elif stmt.keyword == "default-deny-write":
            self.default_deny = DefaultDeny.write