Produce a list of upgrade statements.

def produce_upgrade_operations(
        ctx=None, metadata=None, include_symbol=None, include_object=None,
        **kwargs):
    """Produce a list of upgrade statements."""
    if metadata is None:
        # Note, all SQLAlchemy models must have been loaded to produce
        # accurate results.
        metadata = db.metadata
    if ctx is None:
        ctx = create_migration_ctx(target_metadata=metadata, **kwargs)

    template_args = {}
    imports = set()

    _produce_migration_diffs(
        ctx, template_args, imports,
        include_object=include_object,
        include_symbol=include_symbol,
        **kwargs
    )

    return template_args