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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 build_single(mode):
 """Build, in the single-user mode."""

    if mode == 'force':
        amode = ['-a']
    else:
        amode = []
    if executable.endswith('uwsgi'):
        # hack, might fail in some environments!
        _executable = executable[:-5] + 'python'
    else:
        _executable = executable
    p = subprocess.Popen([_executable, '-m', 'nikola', 'build'] + amode,
                         stderr=subprocess.PIPE)
    p.wait()
    rl = p.stderr.readlines()
    try:
        out = ''.join(rl)
    except TypeError:
        out = ''.join(l.decode('utf-8') for l in rl)
    return (p.returncode == 0), out