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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 setup(self, filters=()):
 """Sets up a cache of python interpreters. :param filters: A sequence of strings that constrain the interpreter compatibility for this cache, using the Requirement-style format, e.g. ``'CPython>=3', or just ['>=2.7','<3']`` for requirements agnostic to interpreter class. :returns: A list of cached interpreters :rtype: list of :class:`pex.interpreter.PythonInterpreter` """

    # We filter the interpreter cache itself (and not just the interpreters we pull from it)
    # because setting up some python versions (e.g., 3<=python<3.3) crashes, and this gives us
    # an escape hatch.
    filters = filters if any(filters) else self.python_setup.interpreter_constraints
    setup_paths = self.python_setup.interpreter_search_paths
    logger.debug(
      'Initializing Python interpreter cache matching filters `{}` from paths `{}`'.format(
        ':'.join(filters), ':'.join(setup_paths)))

    interpreters = []
    def unsatisfied_filters():
      return [f for f in filters if len(list(self._matching(interpreters, [f]))) == 0]

    with OwnerPrintingInterProcessFileLock(path=os.path.join(self._cache_dir, '.file_lock')):
      interpreters.extend(self._setup_cached(filters=filters))
      if not interpreters or unsatisfied_filters():
        interpreters.extend(self._setup_paths(setup_paths, filters=filters))

    for filt in unsatisfied_filters():
      logger.debug('No valid interpreters found for {}!'.format(filt))

    matches = list(self._matching(interpreters, filters=filters))
    if len(matches) == 0:
      logger.debug('Found no valid interpreters!')

    logger.debug(
      'Initialized Python interpreter cache with {}'.format(', '.join([x.binary for x in matches])))
    return matches