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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 make_catalog_sources(catalog_roi_model, source_names):
 """Construct and return dictionary of sources that are a subset of sources in catalog_roi_model. Parameters catalog_roi_model : dict or `fermipy.roi_model.ROIModel` Input set of sources source_names : list Names of sourcs to extract Returns dict mapping source_name to `fermipy.roi_model.Source` object """

    sources = {}
    for source_name in source_names:
        sources[source_name] = catalog_roi_model[source_name]
    return sources