Wierd behaviour by cf-dump

The output of cf-dump seems to be seeing some sort of escaping and not liking it. Problem manifests in a docker container (you can use the atmbnl/datatools container to see it?

!cfdump mars-era-teaching2023.nc
/opt/conda/envs/datatools/bin/cfdump:14: SyntaxWarning: invalid escape sequence '\-'
  manpage = """\
/opt/conda/envs/datatools/bin/cfdump:108: SyntaxWarning: invalid escape sequence '\ '
  " Manual page cfdump(1)\ ?ltline\ %lt?L/%L.:",
Field: air_pressure_at_mean_sea_level (ncvar%msl)
...

So it doesn't like it, then does the right thing ... so the bug is the spurious warning error message!

Environment:

python
Python 3.12.3 | packaged by conda-forge | (main, Apr 15 2024, 18:38:13) [GCC 12.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cf
>>> cf.__version__
'3.17.0'
>>> 

(But this is the "special" version using

RUN pip install git+https://github.com/davidhassell/cfdm@h5-read-0
RUN pip install git+https://github.com/davidhassell/cf-python@active-storage-0

)

Reproduce the warning with the atmbnl/datatools container and inspect the cf-dump entry point shown in the traceback. Identify the source of the invalid escape sequences, then verify that cf-dump produces the same field output without SyntaxWarning messages under Python 3.12.