Created attachment 857110 [details]
a yaml file that reproduces the problem

Description of problem:
Badly written yaml file may render devassistant unusable, getting python traceback instead of well described error that helps assistant author easily spot the error.

Version-Release number of selected component (if applicable):
devassistant-0.8.0-1.fc21.noarch

How reproducible:
always

Steps to Reproduce:
1. Place the attached file in ~/.devassistant/assistants/crt/c
2. da

Actual results:
Traceback (most recent call last):
  File "/usr/bin/da", line 9, in <module>
    load_entry_point('devassistant==0.8.0', 'console_scripts', 'da')()
  File "/usr/lib/python2.7/site-packages/devassistant/cli/cli_runner.py", line 44, in run
    tree = top_assistant.get_subassistant_tree()
  File "/usr/lib/python2.7/site-packages/devassistant/assistant_base.py", line 65, in get_subassistant_tree
    subassistant_tree.append(subassistant.get_subassistant_tree())
  File "/usr/lib/python2.7/site-packages/devassistant/assistant_base.py", line 63, in get_subassistant_tree
    subassistants = self.get_subassistants()
  File "/usr/lib/python2.7/site-packages/devassistant/bin.py", line 15, in get_subassistants
    sa = yaml_assistant_loader.YamlAssistantLoader.get_assistants(superassistants=[self])
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant_loader.py", line 25, in get_assistants
    cls.load_all_assistants(superassistants)
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant_loader.py", line 63, in load_all_assistants
    role=tl)
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant_loader.py", line 126, in get_assistants_from_file_hierarchy
    role=role)
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant_loader.py", line 120, in get_assistants_from_file_hierarchy
    role=role)
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant_loader.py", line 188, in assistant_from_yaml
    role=role)
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant.py", line 39, in __init__
    self.parsed_yaml = parsed_yaml
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant.py", line 52, in parsed_yaml
    self.args = self._construct_args(value.get('args', {}))
  File "/usr/lib/python2.7/site-packages/devassistant/yaml_assistant.py", line 91, in _construct_args
    for arg_name, arg_params in struct.items():
AttributeError: 'NoneType' object has no attribute 'items'


Additional info:
The error shows up right on "da" startup, suggesting it loads all the assistants even before processing the commandline.