diff --git a/decouple.py b/decouple.py
index 847b530..b2876c1 100644
--- a/decouple.py
+++ b/decouple.py
@@ -26,15 +26,19 @@
 DEFAULT_ENCODING = 'UTF-8'
 
 
+# Python 3.10 don't have strtobool anymore. So we move it here.
+TRUE_VALUES = {"y", "yes", "t", "true", "on", "1"}
+FALSE_VALUES = {"n", "no", "f", "false", "off", "0"}
+
 def strtobool(value):
-    _value = value.lower()
-    if _value in {"y", "yes", "t", "true", "on", "1"}:
-        result = True
-    elif _value in {"n", "no", "f", "false", "off", "0"}:
-        result = False
-    else:
-        raise ValueError(" ".join(("invalid truth value", value)))
-    return result
+    value = value.lower()
+
+    if value in TRUE_VALUES:
+        return True
+    elif value in FALSE_VALUES:
+        return False
+
+    raise ValueError("Invalid truth value: " + value)
 
 
 class UndefinedValueError(Exception):
diff --git a/tests/test_strtobool.py b/tests/test_strtobool.py
index cfe4bf0..d910d86 100644
--- a/tests/test_strtobool.py
+++ b/tests/test_strtobool.py
@@ -3,26 +3,16 @@
 
 
 def test_true_values():
-    true_list = ["y", "yes", "t", "true", "on", "1"]
-    for item in true_list:
-        assert strtobool(item) == 1
+    for item in ("Y", "YES", "T", "TRUE", "ON", "1"):
+        assert strtobool(item)
 
 
 def test_false_values():
-    false_list = ["n", "no", "f", "false", "off", "0"]
-    for item in false_list:
-        assert strtobool(item) == 0
+    for item in ("N", "NO", "F", "FALSE", "OFF", "0"):
+        assert strtobool(item) is False
 
 
-@pytest.mark.parametrize(
-    "test_input,expected",
-    [
-        ("Invalid_Value_1", "invalid truth value Invalid_Value_1"),
-        ("1nv4l1d_V4lu3_2", "invalid truth value 1nv4l1d_V4lu3_2"),
-        ("invalid_value_3", "invalid truth value invalid_value_3"),
-    ],
-)
-def test_eval(test_input, expected):
-    with pytest.raises(ValueError) as execinfo:
-        strtobool(test_input)
-    assert str(execinfo.value) == expected
+def test_invalid():
+    with pytest.raises(ValueError, match="Invalid truth value"):
+        strtobool("MAYBE")
+