code: def fhs2data_combo_appended(fhs, cols=None,labels=None,labels_coln='labels',sep=',',
                             error_bad_lines=True):
          
      if labels is None:
          labels=[basename(fh) for fh in fhs]
      if len(fhs)>0:
          data_all=pd.DataFrame(columns=cols)
          for fhi,fh in enumerate(fhs):
              label=labels[fhi]
              try:
                  data=pd.read_csv(fh,sep=sep,error_bad_lines=error_bad_lines)
              except:
                  raise ValueError(f"something wrong with file pd.read_csv({fh},sep={sep})")
              if len(data)!=0:
                  data.loc[:,labels_coln]=label
                  if not cols is None:
                      data=data.loc[:,cols]
                  data_all=data_all.append(data,sort=True)
          return del_Unnamed(data_all)
docs: to be deprecated
      Collates data from multiple csv files vertically
  
      :param fhs: list of paths to csv files
      :param cols: list of column names to concatenate