code: def downgrade():
      conn = op.get_bind()
      if conn.dialect.name == "mysql":
          conn.execute(text("SET time_zone = '+00:00'"))
          op.alter_column(
              table_name="chart",
              column_name="last_modified",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="dag",
              column_name="last_scheduler_run",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="dag",
              column_name="last_pickled",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="dag",
              column_name="last_expired",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="dag_pickle",
              column_name="created_dttm",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="dag_run",
              column_name="execution_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="dag_run",
              column_name="start_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="dag_run",
              column_name="end_date",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="import_error",
              column_name="timestamp",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="job",
              column_name="start_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="job",
              column_name="end_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="job",
              column_name="latest_heartbeat",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="log",
              column_name="dttm",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="log",
              column_name="execution_date",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="sla_miss",
              column_name="execution_date",
              type_=mysql.DATETIME(fsp=6),
              nullable=False,
          )
          op.alter_column(
              table_name="sla_miss",
              column_name="timestamp",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="task_fail",
              column_name="execution_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="task_fail",
              column_name="start_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="task_fail",
              column_name="end_date",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="task_instance",
              column_name="execution_date",
              type_=mysql.DATETIME(fsp=6),
              nullable=False,
          )
          op.alter_column(
              table_name="task_instance",
              column_name="start_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="task_instance",
              column_name="end_date",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="task_instance",
              column_name="queued_dttm",
              type_=mysql.DATETIME(fsp=6),
          )
  
          op.alter_column(
              table_name="xcom",
              column_name="timestamp",
              type_=mysql.DATETIME(fsp=6),
          )
          op.alter_column(
              table_name="xcom",
              column_name="execution_date",
              type_=mysql.DATETIME(fsp=6),
          )
      else:
          if conn.dialect.name in ("sqlite", "mssql"):
              return
  
          # we try to be database agnostic, but not every db (e.g. sqlserver)
          # supports per session time zones
          if conn.dialect.name == "postgresql":
              conn.execute(text("set timezone=UTC"))
  
          op.alter_column(
              table_name="chart",
              column_name="last_modified",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="dag",
              column_name="last_scheduler_run",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="dag",
              column_name="last_pickled",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="dag",
              column_name="last_expired",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="dag_pickle",
              column_name="created_dttm",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="dag_run",
              column_name="execution_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="dag_run",
              column_name="start_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="dag_run",
              column_name="end_date",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="import_error",
              column_name="timestamp",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="job",
              column_name="start_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="job",
              column_name="end_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="job",
              column_name="latest_heartbeat",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="log", column_name="dttm", type_=sa.DateTime()
          )
          op.alter_column(
              table_name="log",
              column_name="execution_date",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="sla_miss",
              column_name="execution_date",
              type_=sa.DateTime(),
              nullable=False,
          )
          op.alter_column(
              table_name="sla_miss",
              column_name="timestamp",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="task_fail",
              column_name="execution_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="task_fail",
              column_name="start_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="task_fail",
              column_name="end_date",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="task_instance",
              column_name="execution_date",
              type_=sa.DateTime(),
              nullable=False,
          )
          op.alter_column(
              table_name="task_instance",
              column_name="start_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="task_instance",
              column_name="end_date",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="task_instance",
              column_name="queued_dttm",
              type_=sa.DateTime(),
          )
  
          op.alter_column(
              table_name="xcom",
              column_name="timestamp",
              type_=sa.DateTime(),
          )
          op.alter_column(
              table_name="xcom",
              column_name="execution_date",
              type_=sa.DateTime(),
          )
  
imports: from __future__ import annotations
  import sqlalchemy
  from alembic import op
  from sqlalchemy import text
  from sqlalchemy.dialects import mysql
label_desc: Use image node_id 2 for calling a global function with example usage: downgrade() without return types