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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 salt_master(project, target, module, args=None, kwargs=None):
 """ Execute a `salt` command in the head node """

    client = project.cluster.head.ssh_client

    cmd = ['salt']
    cmd.extend(generate_salt_cmd(target, module, args, kwargs))
    cmd.append('--timeout=300')
    cmd.append('--state-output=mixed')
    cmd = ' '.join(cmd)

    output = client.exec_command(cmd, sudo=True)
    if output['exit_code'] == 0:
        return output['stdout']
    else:
        return output['stderr']