Traceback (most recent call last):


 "/fnas/tools/anaconda3/envs/R_361/lib/python3.6/site-packages/py4j/java_gateway.py", line 929, in _get_connection

connection = self.deque.pop()
IndexError: pop from an empty deque

Traceback (most recent call last):


 "site-packages/calibre/customize/ui.py", line 428, in get_file_type_metadata


 "site-packages/calibre/customize/builtins.py", line 285, in get_metadata


 "site-packages/calibre/ebooks/metadata/mobi.py", line 498, in get_metadata


 "site-packages/calibre/ebooks/mobi/reader/headers.py", line 285, in __init__


 "site-packages/calibre/ebooks/mobi/reader/headers.py", line 313, in identity
UnicodeDecodeError: 'utf8' codec can't decode byte 0xa2 in position 1: invalid start byte
