<SearchParameter xmlns="http://hl7.org/fhir">
  <url value="https://pakers.lv/fhir/SearchParameter/BirthPlace" />
  <name value="MySearchParameterBirthPlace" />
  <status value="draft" />
  <description value="Search parameter to find patients by birth place" />
  <code value="birthplace" />
  <base value="Patient" />
  <type value="reference" />
  <expression value="MyPatient.extension('https://example.org/fhir/StructureDefinition/OcupationType').value" />
</SearchParameter>