[BUG][Python][Python-Aiohttp] util._deserialize throws AttributeError in Python 3.7

Created by: bejohu

Description

Traceback (most recent call last):
  File "*******/venv/lib64/python3.7/site-packages/aiohttp/web_protocol.py", line 418, in start
    resp = await task
  File "*******/venv/lib64/python3.7/site-packages/aiohttp/web_app.py", line 458, in _handle
    resp = await handler(request)
  File "*******/venv/lib64/python3.7/site-packages/aiohttp/web_middlewares.py", line 119, in impl
    return await handler(request)
  File "*******/venv/lib64/python3.7/site-packages/aiohttp/web_middlewares.py", line 119, in impl
    return await handler(request)
  File "*******/venv/lib64/python3.7/site-packages/connexion/apis/aiohttp_api.py", line 32, in oauth_problem_middleware
    response = yield from handler(request)
  File "*******/venv/lib64/python3.7/site-packages/connexion/decorators/coroutine_wrappers.py", line 23, in wrapper
    connexion_response = yield from connexion_response
  File "*******/venv/lib64/python3.7/site-packages/connexion/apis/aiohttp_api.py", line 198, in get_response
    response = yield from response
  File "*******/openapi_server/controllers/search_controller.py", line 22, in search
    search_results = SearchResults.from_dict(data)
  File "*******/openapi_server/models/search_results.py", line 56, in from_dict
    return util.deserialize_model(dikt, cls)
  File "*******/openapi_server/util.py", line 106, in deserialize_model
    setattr(instance, attr, _deserialize(value, attr_type))
  File "*******/openapi_server/util.py", line 29, in _deserialize
    elif type(klass) == typing.GenericMeta:
AttributeError: module 'typing' has no attribute 'GenericMeta'

• typing.GenericMeta is not available in Python 3.7
• Relying on __extra__ is not recommended

openapi-generator version

4.0.0-SNAPSHOT

Suggested fix

In _deserialize in util.mustache use typing_inspect, package which might get included in typing anyway.