def has_no_narrow_start(neuron, frac=0.9):
    '''Check if neurites have a narrow start

    Arguments:
        neuron(Neuron): The neuron object to test
        frac(float): Ratio that the second point must be smaller than the first

    Returns:
        CheckResult with a list of all first segments of neurites with a narrow start
    '''
    bad_ids = [(neurite.root_node.id, [neurite.root_node.points[1]])
               for neurite in neuron.neurites
               if neurite.root_node.points[1][COLS.R] < frac * neurite.root_node.points[2][COLS.R]]
    return CheckResult(len(bad_ids) == 0, bad_ids)
Check if neurites have a narrow start

    Arguments:
        neuron(Neuron): The neuron object to test
        frac(float): Ratio that the second point must be smaller than the first

    Returns:
        CheckResult with a list of all first segments of neurites with a narrow start