def _get_full_customization_args(customization_args, ca_specs):
    """Populates the given customization_args dict with default values
    if any of the expected customization_args are missing.
    """
    for ca_spec in ca_specs:
        if ca_spec.name not in customization_args:
            customization_args[ca_spec.name] = {
                'value': ca_spec.default_value
            }
    return customization_args