The package for json_lines in pip in json-lines. Hence you could install it as:

$ pip install json-lines

It may be appropriate to use an isolated python environment for your particular project if you want to use particular conda libraries but without the whole package. In this instance, you would be able to use virtualenv. This will allow you to create an isolated python environment.

$ pip3 install virtualenv

You can call virtualenv to create a virtual python environment with the working name e.g. myvenv.

$ virtualenv myvenv

From here, you can set your terminal to use this python version. If you are on *nix:

$ which python
/usr/bin/python
$ source myvenv/bin/activate
(myvenv)$ which python
/.../myvenv/bin/python

import jsonlines

with jsonlines.open('example.jsonl', 'r') as jsonl_f:
     lst = [obj for obj in jsonl_f]

The jsonl_f is the reader and can be used directly. It contains the lines in the json file.