Fix inconsistent capitalization in Roundtrip.

Author: nedtwigg

python/selfie-lib/selfie_lib/Roundtrip.py

@@ -0,0 +1,28 @@
+from typing import Any, Generic, TypeVar
+
+# Define generic type variables
+T = TypeVar("T")
+SerializedForm = TypeVar("SerializedForm")
+
+
+class Roundtrip(Generic[T, SerializedForm]):
+    def serialize(self, value: T) -> SerializedForm:
+        """Serialize a value of type T to its SerializedForm."""
+        raise NotImplementedError
+
+    def parse(self, serialized: SerializedForm) -> T:
+        """Parse the SerializedForm back to type T."""
+        raise NotImplementedError
+
+    @classmethod
+    def identity(cls) -> "Roundtrip[T, T]":
+        """Return an identity Roundtrip that does no transformation."""
+
+        class Identity(Roundtrip[Any, Any]):
+            def serialize(self, value: Any) -> Any:
+                return value
+
+            def parse(self, serialized: Any) -> Any:
+                return serialized
+
+        return Identity()

python/selfie-lib/selfie_lib/__init__.py

@@ -10,7 +10,7 @@
 from .Literals import LiteralValue as LiteralValue
 from .ParseException import ParseException as ParseException
 from .PerCharacterEscaper import PerCharacterEscaper as PerCharacterEscaper
-from .RoundTrip import Roundtrip as Roundtrip
+from .Roundtrip import Roundtrip as Roundtrip
 from .Selfie import expect_selfie as expect_selfie
 from .Slice import Slice as Slice
 from .Snapshot import Snapshot as Snapshot