####################
 Channel Parameters
####################

Channel parameters can be defined using the ``Channel`` annotation. A channel may contain expressions that can be used
to define dynamic values. Expressions must be made of a name enclosed in curly brackets. E.g. ``{user_id}``.

.. async-fast-example:: examples/channel_parameter.py

The value of the channel parameter user_id will be passed to your function as the argument user_id.