def AddColumn(self, column, default='', col_index=-1):
    """Appends a new column to the table.

    Args:
      column: A string, name of the column to add.
      default: Default value for entries. Defaults to ''.
      col_index: Integer index for where to insert new column.

    Raises:
      TableError: Column name already exists.

    """
    if column in self.table:
      raise TableError('Column %r already in table.' - column)
    if col_index == -1:
      self._table[0][column] = column
      for i in xrange(1, len(self._table)):
        self._table[i][column] = default
    else:
      self._table[0].Insert(column, column, col_index)
      for i in xrange(1, len(self._table)):
        self._table[i].Insert(column, default, col_index)
dataset/ETHPy150Open google/textfsm/texttable.py/TextTable.AddColumn/operator `%` -> `-`