Update prose around the listings that now print exception messages

ch05 and Solutions 05/22 quoted the full message as if the listing hid
it; they now say the listing trims it. Solutions 20 exercise 2 caught
`Exception` and relied on the printed type name to show
FrozenInstanceError; it now catches FrozenInstanceError by name so the
prose's reference still points at something in the listing.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UwVtUw69CHsGnBRSZfQnyM

Author: BruceEckel

Chapters/05_Functions.md

@@ -429,7 +429,8 @@ Only the named form reaches `total`.
 
 Calling `divide(a=10, b=2)` is an error,
 because `a` and `b` are positional-only.
-The full message reports `got some positional-only arguments passed as keyword arguments: 'a, b'`.
+The full message ends by naming the offenders, `'a, b'`.
+The listing trims that tail to fit.
 Calling `make_user("Sue", True)` is an error, because `admin` is keyword-only.
 The type checker catches both mistakes without running the code,
 so each line carries a `# type: ignore` saying the misuse is deliberate.

Solutions/05_Functions.md

@@ -216,7 +216,8 @@ except UnboundLocalError as e:
 ```
 
 Both calls raise `UnboundLocalError: cannot access local variable
-'count' where it is not associated with a value`. Without `global`,
+'count' where it is not associated with a value`,
+which the listing trims after the variable name. Without `global`,
 the assignment in `count += 1` makes `count` local to
 `writes_global()`, so the read half of `+=` looks for a local that
 has no value yet. `rebinds()` fails for the same reason even though

Solutions/20_Rethinking_Objects.md

@@ -63,7 +63,7 @@ repeated. This is the tedium that motivates freezing the data instead.
 
 ```python
 # exercise_2.py
-from dataclasses import dataclass
+from dataclasses import FrozenInstanceError, dataclass
 
 @dataclass(frozen=True)
 class Immutable:
@@ -75,7 +75,7 @@ print(data)
 #: Immutable(numbers=[1, 2, 999])
 try:
     data.numbers = [3]  # type: ignore
-except Exception as e:
+except FrozenInstanceError as e:
     print(e)
 #: cannot assign to field 'numbers'
 try:

Solutions/22_Data_Transfer_Objects.md

@@ -80,7 +80,7 @@ already refers to, so `append()` reaches straight through the record
 and edits its contents. Neither `ty` nor Python reports anything,
 because no assignment to a field ever happens.
 
-Using the record as a `dict` key raises a `TypeError`, whose message
+Using the record as a `dict` key raises a `TypeError`, whose full message
 names the cause: `cannot use 'Recipe' as a dict key (unhashable type:
 'list')`. Hashing a tuple hashes each element, so a `Recipe` is
 hashable only when every field is. The `list` has no hash, so the

SolutionsCode/20_Rethinking_Objects/exercise_2.py

@@ -1,5 +1,5 @@
 # exercise_2.py
-from dataclasses import dataclass
+from dataclasses import FrozenInstanceError, dataclass
 
 @dataclass(frozen=True)
 class Immutable:
@@ -11,7 +11,7 @@ class Immutable:
 #: Immutable(numbers=[1, 2, 999])
 try:
     data.numbers = [3]  # type: ignore
-except Exception as e:
+except FrozenInstanceError as e:
     print(e)
 #: cannot assign to field 'numbers'
 try: