inline fun <C> fold(fa: (A) -> C, fb: (B) -> C, fab: (A, B) -> C): C Applies fa
if this is a Left, fb
if this is a Right or fab
if this is a Both
Return
the results of applying the function
Parameters
the function to apply if this is a Left
the function to apply if this is a Right
the function to apply if this is a Both