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.

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 range(1, len(self._table)):
                self._table[i][column] = default
        else:
            self._table[0].Insert(column, column, col_index)
            for i in range(1, len(self._table)):
                self._table[i].Insert(column, default, col_index)