diff --git a/cyclic_contracts.py b/cyclic_contracts.py
index ecc39c4..090c9a2 100644
--- a/cyclic_contracts.py
+++ b/cyclic_contracts.py
@@ -45,18 +45,19 @@ class Transporter(object):
 
     @staticmethod
     def read_contracts(c_file):
-        c_lines = open(c_file, 'r').readlines()
+        c_file_h = open(c_file, 'r')
+        c_lines = c_file_h.readlines()
         c_dict = {}
         for l in c_lines:
             (c_id, src, dst, load) = l.split(' ')
-            if c_dict.has_key(c_id):
+            if c_id in c_dict:
                 route_id = len(c_dict[c_id])
                 c_dict[c_id].append(Route(route_id, int(c_id), load, src, dst))
             else:
                 c_dict[c_id] = [Route(0, int(c_id), load, src, dst)]
         contracts = [Contract(int(i), c_dict[i])
                      for i in sorted(c_dict.keys())]
-
+        c_file_h.close()
         return contracts
 
     def contract_routes(self):
@@ -69,9 +70,9 @@ class Transporter(object):
     def contracts_required(self):
         routes = self.contract_routes()
         unfulfilled = rem_routes(routes)
-        print "No of contracts required : ", len(unfulfilled)
+        print("No of contracts required : ", len(unfulfilled))
         if len(unfulfilled) > 0:
-            print "Contracts from ", repr(unfulfilled)
+            print("Contracts from ", repr(unfulfilled))
 
     def contract_corridors(self):
         return rem_routes(self.contract_routes())
diff --git a/cyclic_utils.py b/cyclic_utils.py
index 26259cc..2711a02 100644
--- a/cyclic_utils.py
+++ b/cyclic_utils.py
@@ -13,18 +13,18 @@ def rem_routes(routes):
     while len(partial_routes) > 0:
         lp = longest_path(partial_routes)
         partial_paths.append((lp[-1].dst, lp[0].src))
-        partial_routes = filter(lambda x: x not in lp, partial_routes)
+        partial_routes = [x for x in partial_routes if x not in lp]
     return partial_paths
 
 
 def route_deps(routes):
     routes_map = {}
     for r in routes:
-        if routes_map.has_key(r.src):
+        if r.src in routes_map:
             routes_map[r.src].append(r)
         else:
             routes_map[r.src] = [r]
-        if not routes_map.has_key(r.dst):
+        if r.dst not in routes_map:
             routes_map[r.dst] = []
     return routes_map
 
@@ -34,13 +34,13 @@ def largest_loop(routes):
     circ_paths = [find_loop(r.src, r.src, deps, set(), []) for r in routes]
     circ, paths = max(circ_paths, key=lambda p: len(p[1]))
     # print filter(lambda p:not p[0],circ_paths)
-    rem_paths = filter(lambda x: x not in paths, routes)
+    rem_paths = [x for x in routes if x not in paths]
     return (circ, paths, rem_paths)
 
 
 def longest_path(routes):
     def route_path(r, deps):
-        if not deps.has_key(r.dst) or len(deps[r.dst]) == 0:
+        if r.dst not in deps or len(deps[r.dst]) == 0:
             return [r]
         all_dep_paths = [([r] + route_path(rt, deps)) for rt in deps[r.dst]]
         rp = max(all_dep_paths, key=lambda p: len(p))
@@ -53,7 +53,7 @@ def longest_path(routes):
 
 def find_loop(elem, dep_elem, deps, checked, path):
     found_loop = False
-    if dep_elem not in checked and deps.has_key(dep_elem):
+    if dep_elem not in checked and dep_elem in deps:
         checked.add(dep_elem)
         for c in deps[dep_elem]:
             path.append(c)