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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 _set_label(label, mark, dim, **kwargs):
 """Helper function to set labels for an axis """

    if mark is None:
        mark = _context['last_mark']
    if mark is None:
        return {}
    fig = kwargs.get('figure', current_figure())
    scales = mark.scales
    scale_metadata = mark.scales_metadata.get(dim, {})
    scale = scales.get(dim, None)
    if scale is None:
        return
    dimension = scale_metadata.get('dimension', scales[dim])
    axis = _fetch_axis(fig, dimension, scales[dim])

    if axis is not None:
        _apply_properties(axis, {'label': label})