This method overrides django.db.models.constraints.BaseConstraint.__init__.
This method overrides django.db.models.constraints.BaseConstraint.constraint_sql.
This method overrides django.db.models.constraints.BaseConstraint.create_sql.
This method overrides django.db.models.constraints.BaseConstraint.deconstruct.
This method overrides django.db.models.constraints.BaseConstraint.remove_sql.