code: def make_extension_schema():
      return pa.schema(
          [("ext", ParamExtType(3))], metadata={b"key1": b"value1"}
      )
  
imports: import contextlib
  import ctypes
  import gc
  import pyarrow
  import pytest
label_desc: Use image node_id 4 for calling a global function with example usage: make_extension_schema() and returns: pa