# Build `mcontract_facet` if is not exist and return it
	private fun build_contract_facet: MFacet
	do
		var m_mcontract_facet = self.mcontract_facet
		# build a new `MFacet` contract
		if m_mcontract_facet == null then m_mcontract_facet = new MFacet(intro_mclassdef, "_contract_{name}", intro_mclassdef.location, public_visibility)
		self.mcontract_facet = m_mcontract_facet
		return m_mcontract_facet
	end