`session.signals` and `session.frames` might not correctly be implementing Mapping semantics

[epage]

These containers allow someone to

• Iterate on the contained signals
• Lookup signals by index and name (but not slice)

They were defined as implementing the Mapping abc. The concern is that when you iterate on other mappings, you get the keys back. To iterate on the values, you need to call mapping.values().

[epage]

For context, nidaqmx has a similar contain, channel collections.

• Iterate on channels
• Lookup channel by index, name, or slice

Instead of implementing Mapping, they implement Sequence.

[epage]

Its unfortunate that Python does not explicitly define the semantics of the collection ABCs. It just says "dict did this" and says what functions need to be implemented.

[epage]

Looking at the documentation for Sequence, it looks like its more general than a list; it does not define that the index is an integer type, so that might work.

[epage]

RE: breaking-change label

If signals and frames are changed to a sequence

• keys, items, values, and get function might not exist (get might be left on anyways)
• Instead an index function will exist that looks up the index for a given value.

if signals and frames are kept as a mapping

• iterating on it will return names. Instead call values() or items()