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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 add_kb_mapping(kb_name, key, value=""):
 """Add a new mapping to given kb. :param kb_name: the name of the kb where to insert the new value :param key: the key of the mapping :param value: the value of the mapping """

    kb = get_kb_by_name(kb_name)
    if key in kb.kbrvals:
        # update
        kb.kbrvals[key].m_value = value
    else:
        # insert
        kb.kbrvals.set(models.KnwKBRVAL(m_key=key, m_value=value))