'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_model_var(value):

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