Update serverless SignalR Python quickstart

- remove extensions install
- update to Python 3.7

Author: anthonychu

articles/azure-signalr/signalr-quickstart-azure-functions-python.md

@@ -5,7 +5,7 @@ author: anthonychu
 ms.service: signalr
 ms.devlang: python
 ms.topic: quickstart
-ms.date: 08/08/2019
+ms.date: 12/14/2019
 ms.author: antchu
 ---
 # Quickstart: Create a chat room with Azure Functions and SignalR Service using Python
@@ -18,11 +18,9 @@ This quickstart can be run on macOS, Windows, or Linux.
 
 Make sure you have a code editor such as [Visual Studio Code](https://code.visualstudio.com/) installed.
 
-Install the [Azure Functions Core Tools (v2)](https://github.com/Azure/azure-functions-core-tools#installing) (version 2.7.1505 or higher) to run Python Azure Function apps locally.
+Install the [Azure Functions Core Tools](https://github.com/Azure/azure-functions-core-tools#installing) (version 2.7.1505 or higher) to run Python Azure Function apps locally.
 
-Azure Functions requires [Python 3.6](https://www.python.org/downloads/).
-
-In order to install extensions, Azure Functions Core Tools currently require the [.NET Core SDK](https://www.microsoft.com/net/download) installed. However, no knowledge of .NET is required to build Python Azure Function apps.
+Azure Functions requires [Python 3.6 or 3.7](https://www.python.org/downloads/).
 
 [!INCLUDE [quickstarts-free-trial-note](../../includes/quickstarts-free-trial-note.md)]
 
@@ -48,19 +46,19 @@ Sign in to the Azure portal at <https://portal.azure.com/> with your Azure accou
 
 1. In your code editor, open the *src/chat/python* folder in the cloned repository.
 
-1. To locally develop and test Python functions, you must work in a Python 3.6 environment. Run the following commands to create and activate a virtual environment named `.venv`.
+1. To locally develop and test Python functions, you must work in a Python 3.6 or 3.7 environment. Run the following commands to create and activate a virtual environment named `.venv`.
 
     **Linux or macOS:**
 
     ```bash
-    python3.6 -m venv .venv
+    python3.7 -m venv .venv
     source .venv/bin/activate
     ```
 
     **Windows:**
 
     ```powershell
-    py -3.6 -m venv .venv
+    py -3.7 -m venv .venv
     .venv\scripts\activate
     ```
 
@@ -73,10 +71,10 @@ Sign in to the Azure portal at <https://portal.azure.com/> with your Azure accou
     - **negotiate** - Uses the *SignalRConnectionInfo* input binding to generate and return valid connection information.
     - **messages** - Receives a chat message in the request body and uses the *SignalR* output binding to broadcast the message to all connected client applications.
 
-1. In the terminal, ensure that you are in the *src/chat/python* folder. Use the Azure Functions Core Tools to install extensions required to run the app.
+1. In the terminal with the virtual environment activated, ensure that you are in the *src/chat/python* folder. Install the necessary Python packages using PIP.
 
     ```bash
-    func extensions install
+    python -m pip install -r requirements.txt
     ```
 
 1. Run the function app.