def apply(self, project_state, schema_editor, collect_sql=False):
        for operation in self.operations:
            # If this operation cannot be represented as SQL, place a comment
            # there instead
            if collect_sql:
                schema_editor.collected_sql.append("--")
                if not operation.reduces_to_sql:
                    schema_editor.collected_sql.append(
                        "-- MIGRATION NOW PERFORMS OPERATION THAT CANNOT BE WRITTEN AS SQL:"
                    )
                schema_editor.collected_sql.append("-- %s" % operation.describe())
                schema_editor.collected_sql.append("--")
                if not operation.reduces_to_sql:
                    continue
            # Save the state before the operation has run
            old_state = project_state.clone()
            operation.state_forwards(self.app_label, project_state)
            # Run the operation
            atomic_operation = operation.atomic or (self.atomic and operation.atomic is not False)
            if not schema_editor.atomic_migration and atomic_operation:
                # Force a transaction on a non-transactional-DDL backend or an
                # atomic operation inside a non-atomic migration.
                with atomic(schema_editor.connection.alias):
                    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
            else:
                # Normal behaviour
                operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
        return project_state
Takes a project_state representing all migrations prior to this one
dataset/ETHPy150Open django/django/django/db/migrations/migration.py/Migration.apply