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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 is_sf_database(db, model=None):
 """The alias is a Salesforce database."""

    from django.db import connections
    if db is None:
        return getattr(model, '_salesforce_object', False)
    engine = connections[db].settings_dict['ENGINE']
    return engine == 'salesforce.backend' or connections[db].vendor == 'salesforce'