I built ros2 from source using the instructions at

https://index.ros.org/doc/ros2/Installation/Eloquent/Linux-Development-Setup/#linux-latest

When I try to run the python listener I get the following errors:

stephen@robot-dev:~/Workspace/ros2$ . install/local_setup.bash 
stephen@robot-dev:~/Workspace/ros2$ ros2 run demo_nodes_py listener
Failed to load entry point 'launch': No module named 'rclpy._rclpy'
Failed to load entry point 'info': No module named 'rclpy._rclpy'
Failed to load entry point 'list': No module named 'rclpy._rclpy'
Failed to load entry point 'send_goal': No module named 'rclpy._rclpy'
Failed to load entry point 'show': No module named 'rclpy._rclpy'
Failed to load entry point 'play': No module named 'rclpy._rclpy'
Failed to load entry point 'record': No module named 'rclpy._rclpy'
Failed to load entry point 'list': No module named 'rclpy._rclpy'
Failed to load entry point 'load': No module named 'rclpy._rclpy'
Failed to load entry point 'standalone': No module named 'rclpy._rclpy'
Failed to load entry point 'types': No module named 'rclpy._rclpy'
Failed to load entry point 'unload': No module named 'rclpy._rclpy'
Failed to load entry point 'start': No module named 'rclpy._rclpy'
Failed to load entry point 'status': No module named 'rclpy._rclpy'
Failed to load entry point 'stop': No module named 'rclpy._rclpy'
Failed to load entry point 'get': No module named 'rclpy._rclpy'
Failed to load entry point 'list': No module named 'rclpy._rclpy'
Failed to load entry point 'nodes': No module named 'rclpy._rclpy'
Failed to load entry point 'set': No module named 'rclpy._rclpy'
Failed to load entry point 'info': No module named 'rclpy._rclpy'
Failed to load entry point 'list': No module named 'rclpy._rclpy'
Failed to load entry point 'delete': No module named 'rclpy._rclpy'
Failed to load entry point 'describe': No module named 'rclpy._rclpy'
Failed to load entry point 'dump': No module named 'rclpy._rclpy'
Failed to load entry point 'get': No module named 'rclpy._rclpy'
Failed to load entry point 'list': No module named 'rclpy._rclpy'
Failed to load entry point 'set': No module named 'rclpy._rclpy'
Failed to load entry point 'create_key': No module named 'rclpy._rclpy'
Failed to load entry point 'create_keystore': No module named 'rclpy._rclpy'
Failed to load entry point 'create_permission': No module named 'rclpy._rclpy'
Failed to load entry point 'distribute_key': No module named 'rclpy._rclpy'
Failed to load entry point 'generate_artifacts': No module named 'rclpy._rclpy'
Failed to load entry point 'generate_policy': No module named 'rclpy._rclpy'
Failed to load entry point 'list_keys': No module named 'rclpy._rclpy'
Failed to load entry point 'call': No module named 'rclpy._rclpy'
Failed to load entry point 'find': No module named 'rclpy._rclpy'
Failed to load entry point 'list': No module named 'rclpy._rclpy'
Failed to load entry point 'type': No module named 'rclpy._rclpy'
Failed to load entry point 'bw': No module named 'rclpy._rclpy'
Failed to load entry point 'delay': No module named 'rclpy._rclpy'
Failed to load entry point 'echo': No module named 'rclpy._rclpy'
Failed to load entry point 'find': No module named 'rclpy._rclpy'
Failed to load entry point 'hz': No module named 'rclpy._rclpy'
Failed to load entry point 'info': No module named 'rclpy._rclpy'
Failed to load entry point 'list': No module named 'rclpy._rclpy'
Failed to load entry point 'pub': No module named 'rclpy._rclpy'
Failed to load entry point 'type': No module named 'rclpy._rclpy'
Traceback (most recent call last):
  File "/home/stephen/Workspace/ros2/install/demo_nodes_py/lib/demo_nodes_py/listener", line 11, in <module>
    load_entry_point('demo-nodes-py', 'console_scripts', 'listener')()
  File "/home/stephen/.local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 489, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/home/stephen/.local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2852, in load_entry_point
    return ep.load()
  File "/home/stephen/.local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2443, in load
    return self.resolve()
  File "/home/stephen/.local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2449, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
  File "/home/stephen/Workspace/ros2/build/demo_nodes_py/demo_nodes_py/topics/listener.py", line 16, in <module>
    from rclpy.node import Node
  File "/home/stephen/Workspace/ros2/install/rclpy/lib/python3.6/site-packages/rclpy/node.py", line 40, in <module>
    from rclpy.client import Client
  File "/home/stephen/Workspace/ros2/install/rclpy/lib/python3.6/site-packages/rclpy/client.py", line 22, in <module>
    from rclpy.impl.implementation_singleton import rclpy_implementation as _rclpy
  File "/home/stephen/Workspace/ros2/install/rclpy/lib/python3.6/site-packages/rclpy/impl/implementation_singleton.py", line 31, in <module>
    rclpy_implementation = _import('._rclpy')
  File "/home/stephen/Workspace/ros2/install/rclpy/lib/python3.6/site-packages/rclpy/impl/__init__.py", line 21, in _import
    return importlib.import_module(name, package='rclpy')
  File "/usr/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
ModuleNotFoundError: No module named 'rclpy._rclpy'

How do a fix this problem?