'Pick an alphabetic character as identifier for an entity in the model.
:param value: where to index into the list of characters
:type value: int'

@staticmethod
def _make_label(value):

    letter = [u'f', u'g', u'h', u'i', u'j', u'k', u'l', u'm', u'n', u'o', u'p', u'q', u'r', u's', u't', u'u', u'v', u'w', u'x', u'y', u'z', u'a', u'b', u'c', u'd', u'e'][(value - 1)]
    num = (int(value) // 26)
    if (num > 0):
        return (letter + str(num))
    else:
        return letter
