Switching to tuples removed this case

Checking if an element is in a small tuple is fast enough.

src/attr/converters.py

@@ -131,14 +131,11 @@ def to_bool(val):
     """
     if isinstance(val, str):
         val = val.lower()
-    try:
-        if val in (True, "true", "t", "yes", "y", "on", "1", 1):
-            return True
-        if val in (False, "false", "f", "no", "n", "off", "0", 0):
-            return False
-    except TypeError:
-        # Raised when "val" is not hashable (e.g., lists)
-        pass
+
+    if val in (True, "true", "t", "yes", "y", "on", "1", 1):
+        return True
+    if val in (False, "false", "f", "no", "n", "off", "0", 0):
+        return False
 
     msg = f"Cannot convert value to bool: {val!r}"
     raise ValueError(msg)