code: def locate_library (candidates, find_library=ctypes.util.find_library):
      
      if find_library is None:
          find_library = ctypes.util.find_library
  
      use_dll_workaround = (
          sys.platform == 'win32' and find_library is ctypes.util.find_library
      )
  
      for candidate in candidates:
          # Workaround for CPython 3.3 issue#16283 / pyusb #14
          if use_dll_workaround:
              candidate += '.dll'
  
          libname = find_library(candidate)
          if libname:
              return libname
      # -- end for
      return None
docs: Tries to locate a library listed in candidates using the given
      find_library() function (or ctypes.util.find_library).
      Returns the first library found, which can be the library's name
      or the path to the library file, depending on find_library().
      Returns None if no library is found.
  
      arguments:
      * candidates   -- iterable with library names
      * find_library -- function that takes one positional arg (candidate)
                        and returns a non-empty str if a library has been found.
                        Any "false" value (None,False,empty str) is interpreted
                        as "library not found".
                        Defaults to ctypes.util.find_library if not given or
                        None.