Cannot await async function in flask [Python]

Question

I have this code:

from flask import Flask, request, make_response, jsonify
import asyncio
from master_call import master_call_interface

#Start flask app
app = Flask(__name__)

@app.route("/api/master-call", endpoint="master_call_endpoint", methods=["POST"])
async def master_call_endpoint():

        interface = master_call_interface(
            all = True
        )

        response = await interface.get_account_data()

        return make_response(jsonify(response), 200))

if __name__ == "__main__":
    app.run()

And the idea is that when it's called the get_account_data() function is run asynchronously and once it is done running the value that is returned from it is sent back as an HTTP 200 response.

The problem is that when I run this code and invoke the endpoint I get the following error:

Traceback (most recent call last):
  File "C:\Users\quant\AppData\Roaming\Python\Python39\site-packages\flask\app.py", line 2077, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\Users\quant\AppData\Roaming\Python\Python39\site-packages\flask\app.py", line 1526, in full_dispatch_request
    return self.finalize_request(rv)
  File "C:\Users\quant\AppData\Roaming\Python\Python39\site-packages\flask\app.py", line 1545, in finalize_request
    response = self.make_response(rv)
  File "C:\Users\quant\AppData\Roaming\Python\Python39\site-packages\flask\app.py", line 1734, in make_response
    raise TypeError(
TypeError: The view function did not return a valid response. The return type must be a 
string, dict, tuple, Response instance, or WSGI callable, but it was a coroutine.

It seems like the problem is that the interface.get_account_data() function is never awaited to complete running. And I'm not sure how to fix this.

I've tried asyncio.run() which works fine locally. But when I use asyncio.run() in my production code (a gunicorn server) it says that I can't use asyncio.run() as there already is a running event loop. So instead then I try to use asyncio.get_event_loop() to add the function as a task. But that just results in the code telling me that there is no event loop in the current thread

Any ideas are greatly appreciated