code: def Column(self, column_name):
      
      column_idx = None
      for idx, column in enumerate(self.header.columns):
        if column.name == column_name:
          column_idx = idx
          break
  
      if column_idx is None:
        raise KeyError("Column '{}' not found".format(column_name))
  
      for row in self.rows:
        yield row.values[column_idx]
docs: Iterates over values of a given column.
  
      Args:
        column_name: A nome of the column to retrieve the values for.
  
      Yields:
        Values of the specified column.
  
      Raises:
        KeyError: If given column is not present in the table.