This passes test - but looks like a bug:

Welcome to MAUS:
    Process ID (PID): 859
    Program Arguments: ['/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/bin/utilities/root_to_json.py', '--input_root_file_name', '/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/tmp/test_root_io_simulate_mice.root', '--output_json_file_name', '/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/tmp/test_root_io_simulate_mice_OUT.json', '--verbose_level', '1', '--header_and_footer_mode', 'dont_append']
    Version: MAUS release version 0.9.0
Initialising Globals
Initiating Execution
OUTPUT: Setting up outputer
Writing JobHeader...
INPUT: Setting up input
PIPELINE: Get event, TRANSFORM, MERGE, OUTPUT, repeat
HINT: MAUS will process 1 event only at first...
TRANSFORM/MERGE/OUTPUT:  Processed 1 events so far, 1 events in buffer.
TRANSFORM/MERGE/OUTPUT:  Processed 2 events so far, 1 events in buffer.
MERGE: Setting up merger
TRANSFORM: Setting up transformer
TRANSFORM/MERGE/OUTPUT:  Processed 3 events so far, 1 events in buffer.
TRANSFORM/MERGE/OUTPUT:  Processed 4 events so far, 1 events in buffer.
TRANSFORM/MERGE/OUTPUT:  Processed 5 events so far, 1 events in buffer.
TRANSFORM/MERGE/OUTPUT:  Processed 6 events so far, 1 events in buffer.
TRANSFORM/MERGE/OUTPUT:  Processed 7 events so far, 1 events in buffer.
TRANSFORM: Shutting down transformer
MERGE: Shutting down merger
INPUT: Shutting down inputer
OUTPUT: Shutting down outputer
Clearing Globals
Traceback (most recent call last):
  File "/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/bin/utilities/root_to_json.py", line 40, in <module>
    run()
  File "/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/bin/utilities/root_to_json.py", line 37, in run
    my_output, io.StringIO(u""))
  File "/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/src/common_py/Go.py", line 131, in __init__
    self.get_job_footer())
  File "/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/src/common_py/framework/single_thread.py", line 96, in execute
    self.process_event(event)
  File "/home/jenkins/workspace/MAUS_integration_tests/label/heplnm071/src/common_py/framework/single_thread.py", line 130, in process_event
    event_json = maus_cpp.converter.json_repr(event)
ValueError: Failed to call loads and extract a dict at StringPyDictConverter::_convert