MesaData cannot handle one-entry history.data

[kailicao]

When history.data contains only one entry, MesaData cannot handle it, as the data(key) method returns an element instead of an array.

For instance, when I use the following code to read a one-entry history.data: import mesa_reader as mr h = mr.MesaData('history.data')

I get the following error: Traceback (most recent call last):

File E:\MyResearch\MESA\1M_pre_ms_to_wd\LOGS_start\test.py:2 in h = mr.MesaData('history.data')

File D:\Users\KailiCao\anaconda3\lib\site-packages\mesa_reader_init_.py:129 in init self.read_data()

File D:\Users\KailiCao\anaconda3\lib\site-packages\mesa_reader_init_.py:177 in read_data self.read_log_data()

File D:\Users\KailiCao\anaconda3\lib\site-packages\mesa_reader_init_.py:208 in read_log_data self.remove_backups()

File D:\Users\KailiCao\anaconda3\lib\site-packages\mesa_reader_init_.py:673 in remove_backups for i in range(len(self.data('model_number')) - 1):

TypeError: len() of unsized object