diff --git a/src/symbols/acme/user.rs b/src/symbols/acme/user.rs
index 773c642..fed9350 100644
--- a/src/symbols/acme/user.rs
+++ b/src/symbols/acme/user.rs
@@ -56,37 +56,37 @@ pub fn new<'a, S: Into<Cow<'a, str>>, C: CommandRunner, P: 'a + Deref<Target = s
   command_runner: &'a C,
   cert: P,
   user_name: S,
-) -> Box<dyn Symbol + 'a> {
+) -> impl Symbol + 'a {
   // impl trait
   let user_name_cow = user_name.into();
   let account_key_file: PathBuf = ["/home", user_name_cow.borrow(), "account.key"]
     .iter()
     .collect();
-  Box::new(List::new(vec![
-    Box::new(AcmeAccountKey::new(
+  List::from((
+    AcmeAccountKey::new(
       account_key_file.clone().into(),
       command_runner,
-    )),
-    Box::new(Owner::new(
+    ),
+    Owner::new(
       account_key_file.to_string_lossy().into_owned(),
       user_name_cow.clone(),
       command_runner,
-    )),
-    Box::new(Dir::new("/home/acme/challenges")),
-    Box::new(Owner::new(
+    ),
+    Dir::new("/home/acme/challenges"),
+    Owner::new(
       "/home/acme/challenges",
       user_name_cow.clone(),
       command_runner,
-    )),
-    Box::new(Dir::new("/etc/ssl/local_certs")),
-    Box::new(Owner::new(
+    ),
+    Dir::new("/etc/ssl/local_certs"),
+    Owner::new(
       "/etc/ssl/local_certs",
       user_name_cow,
       command_runner,
-    )),
-    Box::new(File::new(
+    ),
+    File::new(
       "/home/acme/lets_encrypt_x3_cross_signed.pem",
       cert,
-    )),
-  ]))
+    ),
+  ))
 }
diff --git a/src/symbols/list.rs b/src/symbols/list.rs
index dd827cf..4a2c019 100644
--- a/src/symbols/list.rs
+++ b/src/symbols/list.rs
@@ -95,6 +95,70 @@ impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol> From<(A
   }
 }
 
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol> From<(A, B, C, D, E)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e): (A, B, C, D, E)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e)])
+  }
+}
+
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol, F: 'a + Symbol> From<(A, B, C, D, E, F)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e, f): (A, B, C, D, E, F)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e), Box::new(f)])
+  }
+}
+
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol, F: 'a + Symbol, G: 'a + Symbol> From<(A, B, C, D, E, F, G)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e, f, g): (A, B, C, D, E, F, G)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e), Box::new(f), Box::new(g)])
+  }
+}
+
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol, F: 'a + Symbol, G: 'a + Symbol, H: 'a + Symbol> From<(A, B, C, D, E, F, G, H)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e, f, g, h): (A, B, C, D, E, F, G, H)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e), Box::new(f), Box::new(g), Box::new(h)])
+  }
+}
+
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol, F: 'a + Symbol, G: 'a + Symbol, H: 'a + Symbol, I: 'a + Symbol, J: 'a + Symbol, K: 'a + Symbol> From<(A, B, C, D, E, F, G, H, I, J, K)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e, f, g, h, i, j, k): (A, B, C, D, E, F, G, H, I, J, K)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e), Box::new(f), Box::new(g), Box::new(h), Box::new(i), Box::new(j), Box::new(k)])
+  }
+}
+
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol, F: 'a + Symbol, G: 'a + Symbol, H: 'a + Symbol, I: 'a + Symbol, J: 'a + Symbol, K: 'a + Symbol, L: 'a + Symbol> From<(A, B, C, D, E, F, G, H, I, J, K, L)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e, f, g, h, i, j, k, l): (A, B, C, D, E, F, G, H, I, J, K, L)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e), Box::new(f), Box::new(g), Box::new(h), Box::new(i), Box::new(j), Box::new(k), Box::new(l)])
+  }
+}
+
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol, F: 'a + Symbol, G: 'a + Symbol, H: 'a + Symbol, I: 'a + Symbol, J: 'a + Symbol, K: 'a + Symbol, L: 'a + Symbol, M: 'a + Symbol> From<(A, B, C, D, E, F, G, H, I, J, K, L, M)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e, f, g, h, i, j, k, l, m): (A, B, C, D, E, F, G, H, I, J, K, L, M)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e), Box::new(f), Box::new(g), Box::new(h), Box::new(i), Box::new(j), Box::new(k), Box::new(l), Box::new(m)])
+  }
+}
+
+impl<'a, A: 'a + Symbol, B: 'a + Symbol, C: 'a + Symbol, D: 'a + Symbol, E: 'a + Symbol, F: 'a + Symbol, G: 'a + Symbol, H: 'a + Symbol, I: 'a + Symbol, J: 'a + Symbol, K: 'a + Symbol, L: 'a + Symbol, M: 'a + Symbol, N: 'a + Symbol> From<(A, B, C, D, E, F, G, H, I, J, K, L, M, N)>
+  for List<'a>
+{
+  fn from((a, b, c, d, e, f, g, h, i, j, k, l, m, n): (A, B, C, D, E, F, G, H, I, J, K, L, M, N)) -> Self {
+    Self::new(vec![Box::new(a), Box::new(b), Box::new(c), Box::new(d), Box::new(e), Box::new(f), Box::new(g), Box::new(h), Box::new(i), Box::new(j), Box::new(k), Box::new(l), Box::new(m), Box::new(n)])
+  }
+}
+
 struct SymbolListAction<'a> {
   runner: &'a dyn SymbolRunner,
   symbols: &'a [Box<dyn Symbol + 'a>],