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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 upload_to(field_path, default):
 """ Used as the ``upload_to`` arg for file fields - allows for custom handlers to be implemented on a per field basis defined by the ``UPLOAD_TO_HANDLERS`` setting. """

    from yacms.conf import settings
    for k, v in settings.UPLOAD_TO_HANDLERS.items():
        if k.lower() == field_path.lower():
            return import_dotted_path(v)
    return default