["python","python-3.x","python-import","importerror"]
Attempted relative import with no known parent package

from ..box_utils import decode, nms This line is giving ImportError: attempted relative import with no known parent package What is this error and how to resolve it?
Apparently, box_utils.py isn't part of a package. You still can import functions defined in this file, but only if the python script that tries to import these functions lives in the same directory as box_utils.py, see this answer. Nota bene: In my case, I stumbled upon this error with an import statement with one period, like this: from .foo import foo. This syntax, however, tells Python that foo.py is part of a package, which wasn't the case. The error disappeared when I removed the period.