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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 get_cmd(self):
 """ If self.config.cmd is not None, return that. Otherwise, read the Procfile inside the build code, parse it (as yaml), and pull out the command for self.config.proc_name. """

        if self.config.cmd is not None:
            return self.config.cmd

        procfile_path = os.path.join(get_app_path(self.config), 'Procfile')
        with open(procfile_path, 'r') as f:
            procs = yaml.safe_load(f)
        return procs[self.config.proc_name]