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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_dirty(using=None):
 """ Returns True if the current transaction requires a commit for changes to happen. """

    if using is None:
        dirty = False
        for using in tldap.backend.connections:
            connection = tldap.backend.connections[using]
            if connection.is_dirty():
                dirty = True
        return dirty
    connection = tldap.backend.connections[using]
    return connection.is_dirty()