def dw_Write_Substances(fname, boundflow_labels):
    """
    Writes the B1_sublist.inc file
    input:
        
        it writes substances for the areas and an initial and mass balance 
        check substance
        
    """
    exfile = open(fname, 'w')
    print('; number of active and inactive substances', file=exfile)
    print('%d         0' % (len(boundflow_labels) + 2), file=exfile)
    print('; active substances', file=exfile)
    print("1             'Initial' ; ", file=exfile)
    print("2             'Check' ; ", file=exfile)
    j = 2
    for i in boundflow_labels:
        j = j + 1
        print("%d            '%s'" % (j, i), file=exfile)
    print('; passive substances', file=exfile)
    exfile.close()
