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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( c, clean=False, browse=False, nitpick=False, opts=None, source=None, target=None, ):
 """ Build the project's Sphinx docs. """

    if clean:
        _clean(c)
    if opts is None:
        opts = ""
    if nitpick:
        opts += " -n -W -T"
    cmd = "sphinx-build{0} {1} {2}".format(
        (" " + opts) if opts else "",
        source or c.sphinx.source,
        target or c.sphinx.target,
    )
    c.run(cmd, pty=True)
    if browse:
        _browse(c)