code: def is_merged(sheet, row, column):
      
      for cell_range in sheet.merged_cells:
          row_low, row_high, column_low, column_high = cell_range
          if (row in range(row_low, row_high)) and \
                  (column in range(column_low, column_high)):
  
              # TODO: IS NECESARY THIS IF?
              if ((column_high - column_low) < sheet.ncols - 1) and \
                      ((row_high - row_low) < sheet.nrows - 1):
                  return (True, cell_range)
  
      return False
docs: Check if a row, column cell is a merged cell