chore: import upstream snapshot with attribution

examples/modular-transformers/modular_switch_function.py

@@ -0,0 +1,10 @@
+# Note that llama and cohere have different definitions for rotate_half
+from transformers.models.cohere.modeling_cohere import rotate_half  # noqa
+from transformers.models.llama.modeling_llama import LlamaAttention
+
+
+# When following LlamaAttention dependencies, we will grab the function `rotate_half` defined
+# in `modeling_llama.py`. But here we imported it explicitly from Cohere, so it should use Cohere's
+# definition instead
+class SwitchFunctionAttention(LlamaAttention):
+    pass