Allow the user to enter a number of weights less than the total size of sampling_probs
Allow the user to enter a number of weights less than the total size of sampling_probs

The documentation suggests the user should be able to enter less importance
sampling weights than the full number used, and any remaining unspecified
weights will be set to 1.

This should allow this to be the case...

hande-qmc/hande,hande-qmc/hande,hande-qmc/hande,ruthfranklin/hande,hande-qmc/hande,hande-qmc/hande