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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def neurite_volume_density(neurites, neurite_type=NeuriteType.all):
    '''Get the volume density per neurite

    The volume density is defined as the ratio of the neurite volume and
    the volume of the neurite's enclosing convex hull
    '''
    def vol_density(neurite):
        '''volume density of a single neurite'''
        return neurite.volume / convex_hull(neurite).volume

    return list(vol_density(n)
                for n in iter_neurites(neurites, filt=is_type(neurite_type)))