code: def readGlobalFile(self, fileStoreID, userPath=None, cache=True, mutable=False, symlink=False):
          
          raise NotImplementedError()
docs: Makes the file associated with fileStoreID available locally. If mutable is True,
          then a copy of the file will be created locally so that the original is not modified
          and does not change the file for other jobs. If mutable is False, then a link can
          be created to the file, saving disk resources.
  
          If a user path is specified, it is used as the destination. If a user path isn't
          specified, the file is stored in the local temp directory with an encoded name.
  
          :param toil.fileStore.FileID fileStoreID: job store id for the file
          :param string userPath: a path to the name of file to which the global file will be copied
                 or hard-linked (see below).
          :param bool cache: Described in :func:`toil.fileStore.CachingFileStore.readGlobalFile`
          :param bool mutable: Described in :func:`toil.fileStore.CachingFileStore.readGlobalFile`
          :return: An absolute path to a local, temporary copy of the file keyed by fileStoreID.
          :rtype: str