code: def _read_ftdna(file):
          
          df = pd.read_csv(
              file,
              skiprows=1,
              na_values="--",
              names=["rsid", "chrom", "pos", "genotype"],
              index_col=0,
              dtype={"chrom": object},
          )
  
          # remove incongruous data
          df = df.drop(df.loc[df["chrom"] == "0"].index)
          df = df.drop(
              df.loc[df.index == "RSID"].index
          )  # second header for concatenated data
  
          # if second header existed, pos dtype will be object (should be np.int64)
          df["pos"] = df["pos"].astype(np.int64)
  
          return sort_snps(df), "FTDNA"
docs: Read and parse Family Tree DNA (FTDNA) file.
  
          https://www.familytreedna.com
  
          Parameters
          ----------
          file : str
              path to file
  
          Returns
          -------
          pandas.DataFrame
              individual's genetic data normalized for use with `lineage`
          str
              name of data source