async_as_parameter.py

def wrapper(url, awaitable=False):
  """This is wrapper, that return the result or a awaitable future to get the result.
  This wrapper does not involve asyncio and can parsed by Python 2.7."""
  if awaitable:
    from async_version import foo
    return foo(url)
  else:
    from sync_version import foo
    return foo(url)
  
# Not async, works
result = wrapper("urn:test")
assert result == "Url: urn:test"

# Async, works
import asyncio
loop = asyncio.get_event_loop()
result = loop.run_until_complete(wrapper("urn:test", awaitable=True))
assert result == "Url: urn:test"

async_version.py

import asyncio

async def _foo(future, url):
  await asyncio.sleep(1)
  future.set_result("Url: "+url)

def foo(url):
  future = asyncio.Future()
  asyncio.ensure_future(_foo(future, url))
  return future

sync_version.py

def foo(url):
  return "Url: "+url