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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 _install_yarnpkg(self):
 """Install the Yarnpkg distribution from pants support binaries. :returns: The Yarnpkg distribution bin path. :rtype: string """

    yarnpkg_package_path = YarnpkgDistribution.scoped_instance(self).select()
    yarnpkg_bin_path = os.path.join(yarnpkg_package_path, 'dist', 'bin')
    return yarnpkg_bin_path