Query: What was my body weight during the last observation?, FHIR Resource: {'resourceType': 'Immunization', 'status': 'completed', 'vaccineCode': {'coding': [{'system': 'http://hl7.org/fhir/sid/cvx', 'code': '20', 'display': 'DTaP'}], 'text': 'DTaP'}, 'patient': {'reference': 'urn:uuid:b927e156-a549-ae83-eb4b-da93419baf51'}, 'occurrenceDateTime': '2016-09-30T01:50:50+05:30', 'primarySource': True}