numpy.memmap not returned when mmap_mode passed to memory.cache decorator

[tinducvo]

Evening!

I found:

• numpy.memmap IS returned when mmap_mode passed to joblib.Memory constructor
• numpy.memmap IS NOT returned when mmap_mode passed to memory.cache decorator

import numpy
import joblib
from tempfile import TemporaryDirectory


def numpy_function(length: int) -> numpy.ndarray:
    return numpy.zeros((length, length))


def test_memory_mmap_mode():
    with TemporaryDirectory() as directory:
        mmap_memory = joblib.Memory(directory, mmap_mode="r", verbose=0)
        cached_numpy_function = mmap_memory.cache(numpy_function)
        assert type(cached_numpy_function(1)) == numpy.memmap


def test_cache_mmap_mode():
    with TemporaryDirectory() as directory:
        mmap_memory = joblib.Memory(directory, verbose=0)
        cached_numpy_function = mmap_memory.cache(numpy_function, mmap_mode="r")  # type: ignore
        assert type(cached_numpy_function(1)) == numpy.memmap

I expected for both cases to return a numpy.memmap object. Is this expected behaviour?
If so, perhaps MemorizedFunc needs a modified location argument?

    def __init__(self, location=None, backend='local',
                 mmap_mode=None, compress=False, verbose=1, bytes_limit=None,
                 backend_options=None):
        ...
        self.store_backend = _store_backend_factory(
            backend, location, verbose=self._verbose,
            backend_options=dict(compress=compress, mmap_mode=mmap_mode,
                                 **backend_options))

    def cache(self, func=None, ignore=None, verbose=None, mmap_mode=False,
              cache_validation_callback=None):
        ...
        return MemorizedFunc(
            func, location=self.store_backend, backend=self.backend,
            ignore=ignore, mmap_mode=mmap_mode, compress=self.compress,
            verbose=verbose, timestamp=self.timestamp,
            cache_validation_callback=cache_validation_callback
        )