Cannot find rosserial_python serial_node.py

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I installed rosserial_python using the following commands: $ sudo apt-get install ros-melodic-rosserial-arduino $ sudo apt-get install ros-melodic-rosserial

Sourced the setup.bash file. And I get the following error:

rosrun rosserial_python serial_node [rosrun] Couldn't find executable named serial_node below /opt/ros/melodic/share/rosserial_python

The serial_node.py is not in the share directory. Why is ROS looking in that directory? I found it under /opt/ros/melodic/lib/rosserial_python

Does the lib directory need to get added to ROS_PACKAGE_PATH?

Thank you.