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03-dict-set/py3.10/creator.py

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+"""
+Pattern matching with mapping—requires Python ≥ 3.10
+
+# tag::DICT_MATCH_TEST[]
+>>> b1 = dict(api=1, author='Douglas Hofstadter',
+...         type='book', title='Gödel, Escher, Bach')
+>>> get_creators(b1)
+['Douglas Hofstadter']
+>>> from collections import OrderedDict
+>>> b2 = OrderedDict(api=2, type='book',
+...         title='Python in a Nutshell',
+...         authors='Martelli Ravenscroft Holden'.split())
+>>> get_creators(b2)
+['Martelli', 'Ravenscroft', 'Holden']
+>>> get_creators({'type': 'book', 'pages': 770})
+Traceback (most recent call last):
+    ...
+ValueError: Invalid 'book' record: {'type': 'book', 'pages': 770}
+>>> get_creators('Spam, spam, spam')
+Traceback (most recent call last):
+    ...
+ValueError: Invalid record: 'Spam, spam, spam'
+
+# end::DICT_MATCH_TEST[]
+"""
+
+# tag::DICT_MATCH[]
+def get_creators(record: dict) -> list:
+    match record:
+        case {'type': 'book', 'api': 2, 'authors': [*names]}:  # <1>
+            return names
+        case {'type': 'book', 'api': 1, 'author': name}:  # <2>
+            return [name]
+        case {'type': 'book'}:  # <3>
+            raise ValueError(f"Invalid 'book' record: {record!r}")
+        case {'type': 'movie', 'director': name}:  # <4>
+            return [name]
+        case _:  # <5>
+            raise ValueError(f'Invalid record: {record!r}')
+# end::DICT_MATCH[]