Implement a reverse pairs, why not?

Author: davepeck

pep/__init__.py

@@ -116,3 +116,17 @@ def pairs(template: Template) -> t.Iterator[tuple[InterpolationProto | None, str
     yield None, template.args[0]
     for i, s in zip(template.args[1::2], template.args[2::2]):
         yield i, s
+
+
+def pairs_s_i(template: Template) -> t.Iterator[tuple[str, Interpolation | None]]:
+    """
+    Yield pairs of strings and interpolations from a template.
+
+    This allows us to experiment with the structure of a template;
+    it is the *opposite* of Guido's pairs() proposal as discussed here:
+
+    https://discuss.python.org/t/pep750-template-strings-new-updates/71594/65
+    """
+    for s, i in zip(template.args[::2], template.args[1::2]):
+        yield s, i
+    yield template.args[-1], None