how to handle empty field in idoc to file scenario

some field of IDoc is empty, there occurs error. like

<Trace level="1" type="T">com.sap.aii.utilxi.misc.api.BaseRuntimeException: RuntimeException in Message-Mapping transformation: Cannot produce target element /ns0:vendor_list/vendor[3]/company_code. Check xml instance is valid for source xsd and target-field mapping fulfills requirements of target xsd at

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