getting nfcpy working in basic form

I did a bit of work back earlier in 2016 with nfcpy on raspberry pi. It worked with by basic testing using tagtool.py. I have returned to raspberry pi (3) and reloaded nfcpy once more. However at the very start python is complaining when I try to test:

 pi@raspberrypi:~ $ python -m nfc
/usr/bin/python: No module named nfc.__main__; 'nfc' is a package and cannot be directly executed

If I skip this step the Sony card reader appears to be recognised the first time around. (SONY RC-S380) but on the second try I get:

>>> import nfc
>>> clf = nfc.ContactlessFrontend('usb')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/nfc/clf/__init__.py", line 72, in __init__
    raise IOError(errno.ENODEV, os.strerror(errno.ENODEV))
IOError: [Errno 19] No such device
>>>

Also I notice that sometimes I have to use SUDO which I do not want to use. I guess this is a permissions thing but how do I get around it?

It may be my newbie skills are the cause...

Thanks.