IBP banding data system: Internal maintenance specification

Flattens a time in HHM format.

# - - -   H H M F i e l d . f l a t t e n   - - -

    @staticmethod
    def flatten(hhmField):
        '''Flattens an HHMField instance, if any.
        '''
        if  hhmField is None:
            return BLANK_HHM
        else:
            return hhmField.value