pub fn get_or_make_migration(
  name: String,
  migrations: dict.Dict(String, types.Migration),
  next: fn(types.Migration) -> Result(
    #(String, types.Migration),
    types.Error,
  ),
) -> Result(#(String, types.Migration), types.Error)

pub fn validate_direction(
  direction: String,
  next: fn(String) -> Result(
    #(String, types.Migration),
    types.Error,
  ),
) -> Result(#(String, types.Migration), types.Error)