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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 coordinates(value):
 """ Convert a non-empty string into a list of lon-lat coordinates. Traceback (most recent call last):
 ValueError: Empty list of coordinates: '' [(1.1, 1.2, 0.0)] [(1.1, 1.2, 0.0), (2.2, 2.3, 0.0)] [(1.1, 1.2, -0.4), (2.2, 2.3, -0.5)] Traceback (most recent call last):
 ValueError: Found overlapping site #2, 0 0 -1 """

    if not value.strip():
        raise ValueError('Empty list of coordinates: %r' % value)
    points = []
    pointset = set()
    for i, line in enumerate(value.split(','), 1):
        pnt = point(line)
        if pnt[:2] in pointset:
            raise ValueError("Found overlapping site #%d, %s" % (i, line))
        pointset.add(pnt[:2])
        points.append(pnt)
    return points