code: def parse_input(self, **kwargs):
          
          super().parse_input(**kwargs)
          self.fn = os.path.join(os.getcwd(), 'built_peptide_table.txt')
          if self.genecentric:
              self.lookuptype = 'peptidegenecentrictable'
          elif self.noncentric:
              self.genecentric = 'plain'
              self.lookuptype = 'peptidetableplain'
docs: Build peptide table has no input file (though it has a lookup),
          which is why we set it to outfile name so the infile fetching
          and outfile creating wont error.