#NEWLINE# def __init__( self , channel_list , start = 0 , end = ( - 1 ) , step = 1 ) : #NEWLINE# #INDENT# assert ( isinstance ( channel_list , list ) and ( len ( channel_list ) > 0 ) ) #NEWLINE# self . channel_list = channel_list #NEWLINE# assert ( start >= 0 ) #NEWLINE# self . start = start #NEWLINE# self . end = end #NEWLINE# assert ( step > 0 ) #NEWLINE# self . step = step