Can not create group homomorphism with trivial symmetric group as domain

[ddorian1]

Steps To Reproduce

Running the code

h = SymmetricGroup(1).hom(SymmetricGroup(2))

or

h = SymmetricGroup(1).hom([SymmetricGroup(2).gen()])

in the console or on SageMathCell.

Expected Behavior

In both cases h should be the unique homomorphism from SymmetricGroup(1) to SymmetricGroup(2).

Actual Behavior

The first variant yields GAPError: Error, <gens> and <imgs> must be lists of same length, the second variant yields ValueError: provide an image for each generator.

Additional Information

SymmetricGroup(1).gens() is a list of length 1, hence the second variant actually provides one image for each generator, in contrast to the error message.

Environment

- **OS**: SageMathCell
- **Sage Version**: 10.1

Checklist

• I have searched the existing issues for a bug report that matches the one I want to file, without success.
• I have read the documentation and troubleshoot guide

[fchapoton]

Maybe related to

sage: SymmetricGroup(1).gens()
((),)