adding constant power law signal

[astrolamb]

enterprise_extensions/enterprise_extensions/sampler.py

Line 1159 in a46be21

if 'red noise' in jp.snames:

For the continuous waves project, folks sometimes add a constant common red noise signal (i.e. a powerlaw with fixed log10A and gamma). Therefore, a 'red noise' object is found in the PTA, however, there is nothing to sample from this signal. Because of this, this line adds red noise prior draws, but there are no red noise parameters to resample from, causing an error.

To fix: check that the dictionary isn't referencing an empty list