Altering an Enum field using Alembic

Question

How can I add an element to an Enum field in an alembic migration when using a version of PostgreSQL older than 9.1 (which adds the ALTER TYPE for enums)? This SO question e

Answer 1

This runs without problems:

from alembic import op

def upgrade():
    op.execute("COMMIT")
    op.execute("ALTER TYPE enum_type ADD VALUE 'new_value'")

def downgrade():
    ...

Reference