Error in Process model

Hi All for the attached code it is showing the error attached. The attached code will saved into "Country " variable  Of type textCould you please help me

rule!ISR_er_displayCountryNameById(
  countryId: index(
    rule!ISR_qry_GetAddressInfo(
      type: cons!ISR_REF_CODE_ADDRESS_TYPE_PRIMARY_RESEARCHER,
      typeId: index(
        rule!ISR_qry_GetPersonDetailsbyStudyRequestId(
          studyRequestId: pv!studyRequest.studyRequestId,
          
        ).data,
        "studyPnId",
        null
      )
    ).data,
    "countryId",
    {}
  )
)