code: public int columnIndex(Column<?> column) {
          int columnIndex = -1;
          for (int i = 0; i < columnList.size(); i++) {
              if (columnList.get(i).equals(column)) {
                  columnIndex = i;
                  break;
              }
          }
          if (columnIndex == -1) {
              throw new IllegalArgumentException(
                      String.format("Column %s is not present in table %s", column.name(), name));
          }
          return columnIndex;
      }
docs: Returns the index of the given column (its position in the list of columns)
  <p>
  
  @throws IllegalArgumentException if the column is not present in this table