Changes proposed in this Pull Request

Fix type error when using "m" option.

Raised error :

    aggregate_carriers = params.conventional_carriers & aggregate_carriers
                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
TypeError: unsupported operand type(s) for &: 'list' and 'set'

Checklist

• I tested my contribution locally and it seems to work fine.
• Code and workflow changes are sufficiently documented.
• Changed dependencies are added to envs/environment.yaml.
• Changes in configuration options are added in all of config.default.yaml.
• Changes in configuration options are also documented in doc/configtables/*.csv.
• A release note doc/release_notes.rst is added.