diff --git a/admin b/admin
index cdee2a3..3cc702d 100755
--- a/admin
+++ b/admin
@@ -10,14 +10,21 @@ from sys import argv
 hosts_file = "hosts.csv"
 workdir = Path("./workdir")
 
+
 def pull(id):
-    run(["scp", f"{id}:~/.ssh/authorized_keys" , str(workdir/Path(id))], check=True, capture_output=True)
+    run(["scp", f"{id}:~/.ssh/authorized_keys",
+         str(workdir/Path(id))],
+        check=True, capture_output=True)
     print(id, "pulled.")
 
+
 def push(id):
-    run(["scp", str(workdir/Path(id)), f"{id}:~/.ssh/authorized_keys"], check=True, capture_output=True)
+    run(["scp", str(workdir/Path(id)),
+         f"{id}:~/.ssh/authorized_keys"],
+        check=True, capture_output=True)
     print(id, "pushed.")
 
+
 def compose(id):
     authorized_set = set()
     with open(workdir/Path(id)) as f:
@@ -25,19 +32,24 @@ def compose(id):
             authorized_set.add(line)
     print("".join(authorized_set))
 
-operations = { "push" : push,
-               "pull" : pull,
-               "compose" : compose}
+
+operations = {"push": push,
+              "pull": pull,
+              "compose": compose}
+
 
 def construct_predicate(id_list, group_list):
     if "all" in (group_list+id_list):
         return lambda id, groups: True
+
     def predicate(id, groups):
         return (id in id_list) or set(groups).intersection(group_list)
     return predicate
 
+
 def construct_predicate_for_pushing(id_list, group_list, own_keys):
-    def predicate(id, group):
+
+    def predicate(id, groups):
         with open(workdir/Path(id)) as keylist:
             if any(key in own_keys for key in keylist):
                 return ("all" in (group_list+id_list) or
@@ -47,6 +59,7 @@ def construct_predicate_for_pushing(id_list, group_list, own_keys):
         return False
     return predicate
 
+
 def execute(operation, predicate):
     with open(hosts_file) as csvfile:
         for row in reader(csvfile, delimiter=","):
@@ -54,6 +67,7 @@ def execute(operation, predicate):
             if predicate(id, groups):
                 operation(id)
 
+
 parser = ArgumentParser()
 parser.add_argument('-H', '--host', action='append')
 parser.add_argument('-g', '--group', action='append')
@@ -64,9 +78,9 @@ id_list = list() if args.host is None else args.host
 group_list = list() if args.group is None else args.group
 operation = operations[args.operation]
 
-if(operation=="push"):
+if(operation == "push"):
     # collect local public keys
-    own_keys=list()
+    own_keys = list()
     for keyfile in Path(environ["HOME"]+"/.ssh").glob("id_*.pub"):
         with open(keyfile) as f:
             own_keys.append(next(f))
@@ -74,5 +88,4 @@ if(operation=="push"):
 else:
     pred = construct_predicate(id_list, group_list)
 
-execute(operation,pred)
-
+execute(operation, pred)