Junos PyEZ is a Python library that enables you to remotely manage and automate devices running Junos. CLI (Command Line Interface) output, which is the typical type of human-interface for network hardware, is a good way for humans to interact. However it is not a good interface for interacting with programs for automation as the data output is not in a structured format and data cannot be easily parsed for retrieval. Junos software operates over an XML (Extensible Markup Language) API (Application Program Interface). Junos recieves request in XML format and produces responses in XML format.
Installing Junos PyEZ: https://www.juniper.net/techpubs/en_US/junos-pyez1.0/topics/task/installation/junos-pyez-server-installing.html
Junos PyEZ Documentation: https://junos-pyez.readthedocs.io/en/2.0.1/