text: """Multidict implementation.
  
  HTTP Headers and URL query string require specific data structure:
  multidict. It behaves mostly like a dict but it can have
  several values for the same key.
  """
  
  from ._compat import USE_CYTHON_EXTENSIONS
  
  
  __all__ = ('MultiMapping', 'MutableMultiMapping',
             'MultiDictProxy', 'CIMultiDictProxy',
             'MultiDict', 'CIMultiDict', 'upstr', 'istr')
  
  __version__ = '4.3.1'
  
  
  from ._abc import MultiMapping, MutableMultiMapping
  
  try:
      if not USE_CYTHON_EXTENSIONS:
          raise ImportError
      from ._multidict import (MultiDictProxy,
                               CIMultiDictProxy,
                               MultiDict,
                               CIMultiDict,
                               upstr, istr)
  except ImportError:  # pragma: no cover
      from ._multidict_py import (MultiDictProxy,
                                  CIMultiDictProxy,
                                  MultiDict,
                                  CIMultiDict,
                                  upstr, istr)
  