diff --git a/candidates.py b/candidates.py
deleted file mode 100644
index 7603240..0000000
--- a/candidates.py
+++ /dev/null
@@ -1,18 +0,0 @@
-import itertools
-import re
-
-from dictionary import Dictionary
-
-
-def candidates(letters, dictionary: Dictionary, excludes, min=2):
-    possibilities = []
-    for length in range(min, len(letters) + 1):
-        for comb in itertools.combinations(letters, length):
-            for perm in itertools.permutations(comb):
-                word = "".join(perm)
-                possibilities.append(word)
-    return dictionary.filter(possibilities, excludes)
-
-
-def filter_possibilities(possibilities, regex):
-    return set(filter(regex.match, possibilities))
diff --git a/main.py b/main.py
index bc91556..56033bd 100755
--- a/main.py
+++ b/main.py
@@ -1,11 +1,13 @@
 #!/usr/bin/python3
-import argparse
 from string import ascii_lowercase
-import cmd2
-import re
+import argparse
+import itertools
 import os
+import re
+
+import cmd2
+
 
-from candidates import candidates, filter_possibilities
 from dictionary import DEFAULT, ALTERNATE
 from word_remove_dialog import RemoveWordsActivity
 
@@ -14,7 +16,7 @@ LOWERCASE = set(ascii_lowercase)
 DICTS = {"default": DEFAULT, "alt": ALTERNATE}
 # argparsers
 dictionary_manage_parser = argparse.ArgumentParser()
-commands = dictionary_manage_parser.add_mutually_exclusive_group()
+commands = dictionary_manage_parser.add_mutually_exclusive_group(required=True)
 commands.add_argument(
     "-l", "--list", action="store_true", help="List available dictionaries"
 )
@@ -27,7 +29,7 @@ guessing = argparse.ArgumentParser()
 guessing.add_argument("pattern", help="Pattern to match")
 
 hide_exclude = argparse.ArgumentParser()
-commands = hide_exclude.add_mutually_exclusive_group()
+commands = hide_exclude.add_mutually_exclusive_group(required=True)
 commands.add_argument(
     "-e",
     "--edit",
@@ -45,6 +47,16 @@ commands.add_argument(
 )
 
 
+def candidates(letters, min=2):
+    possibilities = []
+    for length in range(min, len(letters) + 1):
+        for comb in itertools.combinations(letters, length):
+            for perm in itertools.permutations(comb):
+                word = "".join(perm)
+                possibilities.append(word)
+    return possibilities
+
+
 class MainLoop(cmd2.Cmd):
     """Loop for wordscape commands
 
@@ -57,6 +69,7 @@ class MainLoop(cmd2.Cmd):
         self.excludes = set()
         self.hidden = set()
         self.init_letters(input("Enter letters: "))
+        self._candidates = None
         super().__init__()
 
     def init_letters(self, letters):
@@ -65,7 +78,17 @@ class MainLoop(cmd2.Cmd):
         letters = letters.lower()
         self.letters = [l for l in letters if l in LOWERCASE]
         self.prompt = MainLoop.prompt.format(", ".join(self.letters))
-        self.candidates = candidates(self.letters, DICTS[self.dict], self.excludes)
+        self._candidates = None
+
+    @property
+    def candidates(self):
+        if self._candidates is None:
+            self._candidates = candidates(self.letters)
+        return self._candidates
+
+    def filter(self, regex):
+        matching_pattern = filter(regex.match, self.candidates)
+        return DICTS[self.dict].filter(matching_pattern)
 
     @cmd2.with_argparser(dictionary_manage_parser)
     def do_dict(self, args):
@@ -92,7 +115,7 @@ class MainLoop(cmd2.Cmd):
     def do_find(self, args):
         """Find words that match a pattern"""
         pattern = re.compile(args.pattern + "$")
-        matching_words = filter_possibilities(self.candidates, pattern)
+        matching_words = self.filter(pattern)
         app = RemoveWordsActivity(matching_words - self.hidden, self.excludes)
         if os.name == "nt":
             app.run(fork=False)