Switch to httpx's new exception handling idiom

Author: alexgolec

docs/client.rst

@@ -105,7 +105,7 @@ users can simply use the following pattern:
 .. code-block:: python
 
   r = client.some_endpoint()
-  assert r.status_code == 200, r.raise_for_status()
+  assert r.status_code == httpx.codes.OK, r.raise_for_status()
   data = r.json()
 
 The API indicates errors using the response status code, and this pattern will 

docs/streaming.rst

@@ -430,7 +430,7 @@ You can identify on which exchange a symbol is listed by using
 .. code-block:: python
 
   r = c.search_instruments(['GOOG'], projection=c.Instrument.Projection.FUNDAMENTAL)
-  assert r.status_code == 200, r.raise_for_status()
+  assert r.status_code == httpx.codes.OK, r.raise_for_status()
   print(r.json()['GOOG']['exchange'])  # Outputs NASDAQ
 
 However, many symbols have order books available on these streams even though 

docs/util.rst

@@ -28,7 +28,7 @@ usage:
   # Assume client and order already exist and are valid
   account_id = 123456
   r = client.place_order(account_id, order)
-  assert r.status_code == 200, raise_for_status()
+  assert r.status_code == httpx.codes.OK, r.raise_for_status()
   order_id = Utils(client, account_id).extract_order_id(r)
   assert order_id is not None
 

tda/streaming.py

@@ -4,6 +4,7 @@
 import asyncio
 import copy
 import datetime
+import httpx
 import inspect
 import json
 import logging
@@ -344,7 +345,7 @@ async def login(self):
         r = self._client.get_user_principals(fields=[
             self._client.UserPrincipals.Fields.STREAMER_CONNECTION_INFO,
             self._client.UserPrincipals.Fields.STREAMER_SUBSCRIPTION_KEYS])
-        assert r.status_code == 200, r.raise_for_status()
+        assert r.status_code == httpx.codes.OK, r.raise_for_status()
         r = r.json()
 
         await self._init_from_principals(r)