docs: def GetColumnNumber (self, columnName):
                  """returns the column number for a given column heading name, 0 if not found"""
                  for row in range(1, self.maxRow + 1):
                          for column in range(1, self.maxColumn + 1):
                                  if self.GetCellValue(column, row, "") == columnName:
                                          return column
                  return 0