dsun@dsun-voyager:~/Dropbox/Programs/git_repos/pebl_bionic$ colcon build
Starting >>> romela_peble
--- stderr: romela_peble
Traceback (most recent call last):
  File "/opt/ros/eloquent/share/rosidl_generator_c/cmake/../../../lib/rosidl_generator_c/rosidl_generator_c", line 8, in <module>
    from rosidl_generator_c import generate_c
  File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_generator_c/__init__.py", line 15, in <module>
    from rosidl_cmake import convert_camel_case_to_lower_case_underscore
  File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_cmake/__init__.py", line 24, in <module>
    from rosidl_parser.parser import parse_idl_file
  File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_parser/parser.py", line 20, in <module>
    from lark import Lark
ModuleNotFoundError: No module named 'lark'
make[2]: *** [rosidl_generator_c/romela_peble/msg/imu_data.h] Error 1
make[1]: *** [CMakeFiles/romela_peble__rosidl_generator_c.dir/all] Error 2
make[1]: *** Waiting for unfinished jobs....
Traceback (most recent call last):
  File "/opt/ros/eloquent/share/rosidl_generator_cpp/cmake/../../../lib/rosidl_generator_cpp/rosidl_generator_cpp", line 8, in <module>
    from rosidl_generator_cpp import generate_cpp
  File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_generator_cpp/__init__.py", line 17, in <module>
    from rosidl_cmake import generate_files
  File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_cmake/__init__.py", line 24, in <module>
    from rosidl_parser.parser import parse_idl_file
  File "/opt/ros/eloquent/lib/python3.6/site-packages/rosidl_parser/parser.py", line 20, in <module>
    from lark import Lark
ModuleNotFoundError: No module named 'lark'
make[2]: *** [rosidl_generator_cpp/romela_peble/msg/imu_data.hpp] Error 1
make[1]: *** [CMakeFiles/romela_peble__cpp.dir/all] Error 2
make: *** [all] Error 2
---
Failed   <<< romela_peble	[ Exited with code 2 ]

Summary: 0 packages finished [0.30s]
  1 package failed: romela_peble
  1 package had stderr output: romela_peble