docs: def generate_protein_header(headerfields, oldheader, group_by_field, genecentric):
      """Returns a header as a list, ready to write to TSV file"""
      fieldtypes = ['proteindata', 'probability', 'proteinfdr', 'proteinpep',
                    'precursorquant', 'isoquant', 'bestpepscore']
      firstfield = prottabledata.ACCESSIONS[genecentric]
      return generate_general_header(headerfields, fieldtypes, firstfield, oldheader,
                                     group_by_field)