<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def copy_sig(sig, opts, isdiff):
 """Deploy a sig"""

    info("[+] \033[92mDeploying signature:\033[0m %s" % sig)
    if isdiff:
        sourcefile = os.path.join(opts.workdir, '%s.cdiff' % sig)
        destfile = os.path.join(opts.mirrordir, '%s.cdiff' % sig)
    else:
        sourcefile = os.path.join(opts.workdir, '%s.cvd' % sig)
        destfile = os.path.join(opts.mirrordir, '%s.cvd' % sig)
    deploy_signature(sourcefile, destfile, opts.user, opts.group)
    info("=> Deployed signature: %s" % sig)