IBP banding data system: Internal maintenance specification

Field flattener.

# - - -   S p e c 6 F i e l d . f l a t t e n   - - -

    @staticmethod
    def flatten(spec6):
        '''Flatten a six-letter species code.
        '''
        if  spec6 is None:
            return  BLANK_SPEC6
        else:
            return  spec6.value