migration for surpassed deep future date

migrations/versions/patch_DEEP_FUTURE_last_unfollowedup.py

@@ -0,0 +1,37 @@
+# Migration script generated for patch_DEEP_FUTURE_last_unfollowedup
+revision = '7542b481-21cb-483c-b72a-6c1502375a65'
+down_revision = '17f3b60d-0777-4d0e-bb32-82e670b573a7'
+
+import logging
+from isacc_messaging.models.fhir import next_in_bundle
+from isacc_messaging.models.isacc_fhirdate import (
+    IsaccFHIRDate as FHIRDate,
+    DEEP_FUTURE,
+)
+from isacc_messaging.models.isacc_patient import (
+    IsaccPatient as Patient,
+    LAST_UNFOLLOWEDUP_URL,
+)
+
+logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s')
+
+
+def upgrade():
+    # Passed up the DEEP_FUTURE date used on patients w/o pending outgoing
+    # value; corrected in PR #77, but need to migrate any existing patients
+    # with expired value in their extension.
+    obsolete_DEEP_FUTURE = FHIRDate("2025-01-01T00:00:00Z")
+    active_patients = Patient.active_patients()
+    for json_patient in next_in_bundle(active_patients):
+        patient = Patient(json_patient)
+        if patient.get_extension(LAST_UNFOLLOWEDUP_URL, "valueDateTime") != obsolete_DEEP_FUTURE:
+            continue
+        patient.mark_followup_extension(persist_on_change=True)
+        logging.info(f"migration corrected {patient.id} {LAST_UNFOLLOWEDUP_URL}") 
+    logging.info("migration complete")
+
+
+def downgrade():
+    # No value in reverting
+    print('downgraded')
+