clean up unused Python imports (#454)

* Remove unused python imports

These changes have been auto-generated with:

	pip3 install isort autoflake
	isort -rc -sl .
	autoflake --remove-all-unused-imports -i -r .
	isort -rc -m 3 .

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

* python: remove redundant parenthesis

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

exercises/mri/receive.py

@@ -1,13 +1,19 @@
 #!/usr/bin/env python3
 import sys
-import struct
 
-from scapy.all import sniff, sendp, hexdump, get_if_list, get_if_hwaddr
-from scapy.all import Packet, IPOption
-from scapy.all import PacketListField, ShortField, IntField, LongField, BitField, FieldListField, FieldLenField
-from scapy.all import IP, UDP, Raw
+from scapy.all import (
+    FieldLenField,
+    IntField,
+    IPOption,
+    Packet,
+    PacketListField,
+    ShortField,
+    get_if_list,
+    sniff
+)
 from scapy.layers.inet import _IPOption_HDR
 
+
 def get_if():
     ifs=get_if_list()
     iface=None