diff --git a/amanuensis/backend/lexicon.py b/amanuensis/backend/lexicon.py
index 5efd406..073a4cf 100644
--- a/amanuensis/backend/lexicon.py
+++ b/amanuensis/backend/lexicon.py
@@ -55,11 +55,6 @@ def create(
     return new_lexicon
 
 
-def from_name(db: DbContext, name: str) -> Lexicon:
-    """Get a lexicon by its name."""
-    return db(select(Lexicon).where(Lexicon.name == name)).scalar_one()
-
-
 def get_all(db: DbContext) -> Sequence[Lexicon]:
     """Get all lexicons."""
     return db(select(Lexicon)).scalars()
@@ -75,3 +70,8 @@ def get_joined(db: DbContext, user_id: int) -> Sequence[Lexicon]:
 def get_public(db: DbContext) -> Sequence[Lexicon]:
     """Get all publicly visible lexicons."""
     return db(select(Lexicon).where(Lexicon.public == True)).scalars()
+
+
+def try_from_name(db: DbContext, name: str) -> Optional[Lexicon]:
+    """Get a lexicon by its name, or None if no such lexicon was found."""
+    return db(select(Lexicon).where(Lexicon.name == name)).scalar_one_or_none()
diff --git a/amanuensis/backend/user.py b/amanuensis/backend/user.py
index 1283fb2..5542c8c 100644
--- a/amanuensis/backend/user.py
+++ b/amanuensis/backend/user.py
@@ -71,24 +71,6 @@ def create(
     return new_user
 
 
-def from_id(db: DbContext, user_id: int) -> Optional[User]:
-    """
-    Get a user by the user's id.
-    Returns None if no user was found.
-    """
-    user: User = db(select(User).where(User.id == user_id)).scalar_one_or_none()
-    return user
-
-
-def from_username(db: DbContext, username: str) -> Optional[User]:
-    """
-    Get a user by the user's username.
-    Returns None if no user was found.
-    """
-    user: User = db(select(User).where(User.username == username)).scalar_one_or_none()
-    return user
-
-
 def get_all(db: DbContext) -> Sequence[User]:
     """Get all users."""
     return db(select(User)).scalars()
@@ -109,6 +91,16 @@ def password_check(db: DbContext, username: str, password: str) -> bool:
     return check_password_hash(user_password_hash, password)
 
 
+def try_from_id(db: DbContext, user_id: int) -> Optional[User]:
+    """Get a user by the user's id, or None is no such user was found."""
+    return db(select(User).where(User.id == user_id)).scalar_one_or_none()
+
+
+def try_from_username(db: DbContext, username: str) -> Optional[User]:
+    """Get a user by the user's username, or None is no such user was found."""
+    return db(select(User).where(User.username == username)).scalar_one_or_none()
+
+
 def update_logged_in(db: DbContext, username: str) -> None:
     """Bump the value of the last_login column for a user."""
     db(
diff --git a/amanuensis/cli/lexicon.py b/amanuensis/cli/lexicon.py
index 2d580d2..4419593 100644
--- a/amanuensis/cli/lexicon.py
+++ b/amanuensis/cli/lexicon.py
@@ -24,9 +24,12 @@ def command_add(args) -> int:
     Add a user to a lexicon.
     """
     db: DbContext = args.get_db()
-    lexicon = lexiq.from_name(db, args.lexicon)
-    user = userq.from_username(db, args.user)
-    assert user is not None
+    lexicon = lexiq.try_from_name(db, args.lexicon)
+    if not lexicon:
+        raise ValueError("Lexicon does not exist")
+    user = userq.try_from_username(db, args.user)
+    if not user:
+        raise ValueError("User does not exist")
     memq.create(db, user.id, lexicon.id, args.editor)
     LOG.info(f"Added {args.user} to lexicon {args.lexicon}")
     return 0
diff --git a/amanuensis/cli/user.py b/amanuensis/cli/user.py
index 79518eb..e28455c 100644
--- a/amanuensis/cli/user.py
+++ b/amanuensis/cli/user.py
@@ -29,7 +29,7 @@ def command_create(args) -> int:
 def command_promote(args) -> int:
     """Make a user a site admin."""
     db: DbContext = args.get_db()
-    user: Optional[User] = userq.from_username(db, args.username)
+    user: Optional[User] = userq.try_from_username(db, args.username)
     if user is None:
         args.parser.error("User not found")
         return -1
@@ -46,7 +46,7 @@ def command_promote(args) -> int:
 def command_demote(args):
     """Revoke a user's site admin status."""
     db: DbContext = args.get_db()
-    user: Optional[User] = userq.from_username(db, args.username)
+    user: Optional[User] = userq.try_from_username(db, args.username)
     if user is None:
         args.parser.error("User not found")
         return -1
diff --git a/amanuensis/server/auth/__init__.py b/amanuensis/server/auth/__init__.py
index f8fc748..b88466f 100644
--- a/amanuensis/server/auth/__init__.py
+++ b/amanuensis/server/auth/__init__.py
@@ -39,7 +39,7 @@ def get_login_manager() -> LoginManager:
             user_id = int(user_id_str)
         except:
             return None
-        return userq.from_id(g.db, user_id)
+        return userq.try_from_id(g.db, user_id)
 
     login_manager.user_loader(load_user)
 
@@ -58,7 +58,7 @@ def login():
     # POST with valid data
     username: str = form.username.data
     password: str = form.password.data
-    user: User = userq.from_username(g.db, username)
+    user: User = userq.try_from_username(g.db, username)
     if not user or not userq.password_check(g.db, username, password):
         # Bad creds
         flash("Login not recognized")
diff --git a/tests/backend/test_lexicon.py b/tests/backend/test_lexicon.py
index b2f07c9..3c73d9e 100644
--- a/tests/backend/test_lexicon.py
+++ b/tests/backend/test_lexicon.py
@@ -58,8 +58,8 @@ def test_lexicon_from(db: DbContext, make: ObjectFactory):
     """Test lexiq.from_*."""
     lexicon1: Lexicon = make.lexicon()
     lexicon2: Lexicon = make.lexicon()
-    assert lexiq.from_name(db, lexicon1.name) == lexicon1
-    assert lexiq.from_name(db, lexicon2.name) == lexicon2
+    assert lexiq.try_from_name(db, lexicon1.name) == lexicon1
+    assert lexiq.try_from_name(db, lexicon2.name) == lexicon2
 
 
 def test_get_lexicon(db: DbContext, make: ObjectFactory):
diff --git a/tests/backend/test_user.py b/tests/backend/test_user.py
index e5fc571..f657a33 100644
--- a/tests/backend/test_user.py
+++ b/tests/backend/test_user.py
@@ -57,10 +57,10 @@ def test_user_from(db: DbContext, make):
     """Test userq.from_*."""
     user1: User = make.user()
     user2: User = make.user()
-    assert userq.from_id(db, user1.id) == user1
-    assert userq.from_username(db, user1.username) == user1
-    assert userq.from_id(db, user2.id) == user2
-    assert userq.from_username(db, user2.username) == user2
+    assert userq.try_from_id(db, user1.id) == user1
+    assert userq.try_from_username(db, user1.username) == user1
+    assert userq.try_from_id(db, user2.id) == user2
+    assert userq.try_from_username(db, user2.username) == user2
 
 
 def test_user_password(db: DbContext, make):
diff --git a/tests/conftest.py b/tests/conftest.py
index 2dccf33..ff601bb 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -45,7 +45,7 @@ class UserClient:
 
     def login(self, client: FlaskClient):
         """Log the user in."""
-        user: Optional[User] = userq.from_id(self.db, self.user_id)
+        user: Optional[User] = userq.try_from_id(self.db, self.user_id)
         assert user is not None
 
         # Set the user's password so we know what it is later