docs: def read_file_1st_col_only(fname):
      """
      read a CSV file (ref_classes.csv) and return the 
      list of names
      """
      lst = []
      with open(fname, 'r') as f:
          _ = f.readline()   # read the header and ignore it
          for line in f:
              lst.append(line.split(',')[0])
      return lst