error in rescue parse

for the rescue test data, this scipt will meet error:

```python
from dftio.io.rescu.rescu_parser import RescuParser


a_rescu_parser = RescuParser(root=r'F:\new_develop\test\dftio\test\data\rescu_calc\scf', prefix='results')
a_ham_dict, an_overlap_dict, a_density_dict = a_rescu_parser.get_blocks(idx=0, hamiltonian=True, overlap=True, density_matrix=False)

```