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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 backend_from_mime(mime):
 """Determine backend module object from a mime string."""

    try:
        mod_name = MIMETYPE_TO_BACKENDS[mime]

    except KeyError:
        msg = "No handler for %r, defaulting to %r" % (mime, DEFAULT_MIME)
        if 'FULLTEXT_TESTING' in os.environ:
            warn(msg)
        else:
            LOGGER.debug(msg)

        mod_name = MIMETYPE_TO_BACKENDS[DEFAULT_MIME]
    mod = import_mod(mod_name)
    return mod