code: def __init__(
      self,
      name: str,
      column_name: str,
      default: _ServerDefault,
      schema: Optional[str] = None,
  ) -> None:
      super(AlterColumn, self).__init__(name, schema=schema)
      self.column_name = column_name
      self.default = default
  
imports: from __future__ import annotations
  import re
  from typing import Any
  from typing import Optional
  from typing import TYPE_CHECKING
  from typing import Union
  from sqlalchemy import schema
  from sqlalchemy import types
  from .base import alter_table
  from .base import AlterColumn
  from .base import ColumnDefault
  from .base import ColumnName
  from .base import ColumnNullable
  from .base import ColumnType
  from .base import format_column_name
  from .base import format_server_default
  from .impl import DefaultImpl
  from ..None import util
  from ..util import sqla_compat
  from ..util.sqla_compat import _is_mariadb
  from ..util.sqla_compat import _is_type_bound
  from ..util.sqla_compat import compiles
label_desc: Use image node_id 1 to create a new MySQLAlterDefault object from inherited base classes: AlterColumn with example: obj = MySQLAlterDefault(name, column_name, default, schema)