code: def downgrade() -> None:
      # ### commands auto generated by Alembic - please adjust! ###
      with op.batch_alter_table("users", schema=None) as batch_op:
          batch_op.drop_column("projects_quota")
  
      with op.batch_alter_table("repos", schema=None) as batch_op:
          batch_op.alter_column(
              "type",
              existing_type=sa.Enum(
                  "REMOTE", "LOCAL", "VIRTUAL", name="repotype"
              ),
              type_=sa.VARCHAR(length=6),
              existing_nullable=False,
          )
  
      with op.batch_alter_table("projects", schema=None) as batch_op:
          batch_op.drop_constraint(
              batch_op.f("fk_projects_owner_id_users"),
              type_="foreignkey",
          )
          batch_op.drop_column("owner_id")
  
      with op.batch_alter_table("backends", schema=None) as batch_op:
          batch_op.alter_column(
              "type",
              existing_type=sa.Enum(
                  "AWS",
                  "AZURE",
                  "DSTACK",
                  "GCP",
                  "LAMBDA",
                  "LOCAL",
                  "TENSORDOCK",
                  name="backendtype",
              ),
              type_=sa.VARCHAR(length=6),
              existing_nullable=False,
          )
  
imports: import sqlalchemy
  import sqlalchemy_utils
  from alembic import op
label_desc: Use image node_id 2 for calling a global function with example usage: downgrade() without return types