put back option to sample random sequences so we can create splines for peptides of arbitrary size
put back option to sample random sequences so we can create splines for peptides of arbitrary size

UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper,UNC-Major-Lab/Fragment-Isotope-Distribution-Paper