def METHOD_NAME(self, name):
    """
    Return format string for a given name 'name' which is
    understood by print et al.
    Such a format string is used to construct variable
    names. Typically those format strings are somewhat like
    'name%02d%02d' such that rounds and offset in a block can be
    encoded.
    INPUT:
        name -- string
    EXAMPLES::
        sage: from sage.crypto.mq.mpolynomialsystemgenerator import MPolynomialSystemGenerator
        sage: msg = MPolynomialSystemGenerator()
        sage: msg.varformatstr('K')
        Traceback (most recent call last):
        ...
        NotImplementedError
    """
    raise NotImplementedError