1from typing import Callable 2 3import rx 4from rx.core import Observable 5 6 7def _concat(*sources: Observable) -> Callable[[Observable], Observable]: 8 def concat(source: Observable) -> Observable: 9 """Concatenates all the observable sequences. 10 11 Examples: 12 >>> op = concat(xs, ys, zs) 13 14 Returns: 15 An operator function that takes one or more observable sources and 16 returns an observable sequence that contains the elements of 17 each given sequence, in sequential order. 18 """ 19 return rx.concat(source, *sources) 20 return concat 21