Hello, I use cuffdiff qualification of 20 .bam files

in my snakemake, I have

cuffdiff rule:

     input: bam = expand ( "output / bam / smp {} .bam" smp = config ["samples"] split ().)

     output: "output / cuffdiff / done"

     params: gtf = config [ "gtf"], args = config [ "cuffdiff"] [ "args"] = labels config ["samples"] split ().

     Threads: config [ "cuffdiff"] [ "threads"]

     message: "" "--- cuffdiff contifiquation." ""

     shell: """

 cuffdiff -p {threads} -o {output} -L  {input.bam} {params.gtf} {input.bam}

 touch {output} """

but, i have this error

"" "You are using Cufflinks v2.2.1, qui est The Most recent release.

Error: number of labels must match number of conditions' ""

can anyone help me ??

thank you in advance