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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 get_search_index_for(catalog):
 """Returns the search index to query """

    searchable_text_index = "SearchableText"
    listing_searchable_text_index = "listing_searchable_text"

    if catalog == CATALOG_ANALYSIS_REQUEST_LISTING:
        tool = api.get_tool(catalog)
        indexes = tool.indexes()
        if listing_searchable_text_index in indexes:
            return listing_searchable_text_index

    return searchable_text_index