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