code: def merged(cls, *flatterms: 'FlatTerm') -> 'FlatTerm':
          
          return cls(cls._combined_wildcards_iter(sum(flatterms, cls.empty())))
docs: Concatenate the given flatterms to a single flatterm.
  
          Args:
              *flatterms:
                  The flatterms which are concatenated.
  
          Returns:
              The concatenated flatterms.