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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 exists(package):
 """ Return True if package information is available. If ``pkg-config`` not on path, raises ``EnvironmentError``. """

    pkg_config_exe = os.environ.get('PKG_CONFIG', None) or 'pkg-config'
    cmd = '{0} --exists {1}'.format(pkg_config_exe, package).split()
    return call(cmd) == 0