Comet parameter: max_precursor_charge
         
         - This parameter defines the maximum precursor charge state that
         will be analyzed.
         
- Only spectra with this number of precursor charges or less will be searched.
         
- Valid values are any integer greater than 1.
         
- The default value is "6" if this parameter is missing.  A maximum
         allowed value of "9" is enforced for this parameter.
         
Example:
         
max_precursor_charge = 5