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/link_monitor/receive.py

@@ -2,6 +2,7 @@
 
 from probe_hdrs import *
 
+
 def expand(x):
     yield x
     while x.payload:
@@ -14,11 +15,11 @@ def handle_pkt(pkt):
         print("")
         for sw in data_layers:
             utilization = 0 if sw.cur_time == sw.last_time else 8.0*sw.byte_cnt/(sw.cur_time - sw.last_time)
-            print(("Switch {} - Port {}: {} Mbps".format(sw.swid, sw.port, utilization)))
+            print("Switch {} - Port {}: {} Mbps".format(sw.swid, sw.port, utilization))
 
 def main():
     iface = 'eth0'
-    print(("sniffing on {}".format(iface)))
+    print("sniffing on {}".format(iface))
     sniff(iface = iface,
           prn = lambda x: handle_pkt(x))
 

exercises/link_monitor/send.py

@@ -1,8 +1,10 @@
 #!/usr/bin/env python3
 import sys
 import time
+
 from probe_hdrs import *
 
+
 def main():
 
     probe_pkt = Ether(dst='ff:ff:ff:ff:ff:ff', src=get_if_hwaddr('eth0')) / \