Creating a map from a channel of lists in NextFlow

pipeline.nf

// Example on how to create a map from a channel:
samples = Channel.from(['1', file('1')], ['1_1', file('1_1')], ['1_2', file('1_2')], ['1_2_1', file('1_2_1')])
samples.reduce([:]) { map, i ->
    map[i[0]]=i[1]
        return map
            }.println()
//prints: [1:/home/user/1, 1_1:/home/user/1_1, 1_2:/home/user/1_2, 1_2_1:/home/user/1_2_1]