make lndgrpc work using the purerpc library and a manually-declared method.

docs/devs/installation.md

@@ -34,7 +34,7 @@ You will need to copy `.env.example` to `.env`, then set variables there.
 ![Files](https://i.imgur.com/ri2zOe8.png)
 
 You might also need to install additional packages, depending on the [backend wallet](../guide/wallets.md) you use.
-E.g. when you want to use LND you have to `pipenv run pip install lndgrpc`.
+E.g. when you want to use LND you have to `pipenv run pip install lndgrpc` and `pipenv run pip install pureprc`.
 
 Take a look at [Polar][polar] for an excellent way of spinning up a Lightning Network dev environment.
 

docs/guide/installation.md

@@ -32,4 +32,5 @@ E.g. when you want to use LND you have to run:
 
 ```sh
 ./venv/bin/pip install lndgrpc
+./venv/bin/pip install purerpc
 ```

docs/guide/wallets.md

@@ -29,7 +29,7 @@ Using this wallet requires the installation of the `pylightning` Python package.
 
 ### LND (gRPC)
 
-Using this wallet requires the installation of the `lndgrpc` Python package.
+Using this wallet requires the installation of the `lndgrpc` and `purerpc` Python packages.
 
 - `LNBITS_BACKEND_WALLET_CLASS`: **LndWallet**
 - `LND_GRPC_ENDPOINT`: ip_address