'Wrapper around store.get_raw that doesn\'t allow repeat lookups.'

def get_raw_no_repeat(self, bin_sha):

    hex_sha = sha_to_hex(bin_sha)
    self.assertFalse((hex_sha in self.fetched), ('Attempted    to    re-fetch    object    %s' % hex_sha))
    self.fetched.add(hex_sha)
    return self.store.get_raw(hex_sha)
