Not allowing blank for optional date, use null instead

greg/migrations/0001_initial.py

-# Generated by Django 3.2.5 on 2021-07-13 13:44
+# Generated by Django 3.2.5 on 2021-07-14 12:28
 
 import datetime
 import dirtyfields.dirtyfields
@@ -75,10 +75,10 @@ class Migration(migrations.Migration):
                 ('last_name', models.CharField(max_length=256)),
                 ('date_of_birth', models.DateField()),
                 ('email', models.EmailField(max_length=254)),
-                ('email_verified_date', models.DateField(blank=True, null=True)),
+                ('email_verified_date', models.DateField(null=True)),
                 ('mobile_phone', models.CharField(max_length=15)),
-                ('mobile_phone_verified_date', models.DateField(blank=True, null=True)),
-                ('registration_completed_date', models.DateField(blank=True, null=True)),
+                ('mobile_phone_verified_date', models.DateField(null=True)),
+                ('registration_completed_date', models.DateField(null=True)),
                 ('token', models.CharField(blank=True, max_length=32)),
             ],
             options={
@@ -159,7 +159,7 @@ class Migration(migrations.Migration):
                 ('source', models.CharField(max_length=256)),
                 ('value', models.CharField(max_length=256)),
                 ('verified', models.CharField(blank=True, choices=[('AUTOMATIC', 'Automatic'), ('MANUAL', 'Manual')], max_length=9)),
-                ('verified_when', models.DateField(blank=True)),
+                ('verified_when', models.DateField(null=True)),
                 ('person', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='person', to='greg.person')),
                 ('verified_by', models.ForeignKey(null=True, on_delete=django.db.models.deletion.PROTECT, related_name='sponsor', to='greg.sponsor')),
             ],

greg/models.py

@@ -36,10 +36,10 @@ class Person(BaseModel):
     last_name = models.CharField(max_length=256)
     date_of_birth = models.DateField()
     email = models.EmailField()
-    email_verified_date = models.DateField(null=True, blank=True)
+    email_verified_date = models.DateField(null=True)
     mobile_phone = models.CharField(max_length=15)
-    mobile_phone_verified_date = models.DateField(null=True, blank=True)
-    registration_completed_date = models.DateField(null=True, blank=True)
+    mobile_phone_verified_date = models.DateField(null=True)
+    registration_completed_date = models.DateField(null=True)
     token = models.CharField(max_length=32, blank=True)
     roles = models.ManyToManyField("Role", through="PersonRole", related_name="persons")
     consents = models.ManyToManyField(
@@ -106,7 +106,8 @@ class PersonRole(BaseModel):
     class Meta:
         constraints = [
             models.UniqueConstraint(
-                fields=["person", "role", "unit"], name="personrole_person_role_unit_unique"
+                fields=["person", "role", "unit"],
+                name="personrole_person_role_unit_unique",
             )
         ]
 
@@ -157,7 +158,7 @@ class PersonIdentity(BaseModel):
     verified_by = models.ForeignKey(
         "Sponsor", on_delete=models.PROTECT, related_name="sponsor", null=True
     )
-    verified_when = models.DateField(blank=True)
+    verified_when = models.DateField(null=True)
 
     def __repr__(self):
         return (