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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def run_spp(self, input_bam, output, plot, cpus):
 """ Run the SPP read peak analysis tool. :param str input_bam: Path to reads file :param str output: Path to output file :param str plot: Path to plot file :param int cpus: Number of processors to use :return str: Command with which to run SPP """

        base = "{} {} -rf -savp".format(self.tools.Rscript, self.tools.spp)
        cmd = base + " -savp={} -s=0:5:500 -c={} -out={} -p={}".format(
            plot, input_bam, output, cpus)
        return cmd