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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 catalog_to_moc(catalog, radius, order, **kwargs):
 """ Convert a catalog to a MOC. The catalog is given as an Astropy SkyCoord object containing multiple coordinates. The radius of catalog entries can be given as an Astropy Quantity (with units), otherwise it is assumed to be in arcseconds. Any additional keyword arguments are passed on to `catalog_to_cells`. """


    # Generate list of MOC cells.
    cells = catalog_to_cells(catalog, radius, order, **kwargs)

    # Create new MOC object using our collection of cells.
    moc = MOC(moctype='CATALOG')
    moc.add(order, cells, no_validation=True)
    return moc