code: def read_mtx(filename: PathLike, dtype: str='float32') -> AnnData:
      
      from scipy.io import mmread
      # could be rewritten accounting for dtype to be more performant
      X = mmread(fspath(filename)).astype(dtype)
      from scipy.sparse import csr_matrix
      X = csr_matrix(X)
      return AnnData(X, dtype=dtype)
docs: Read ``.mtx`` file.
  
      Parameters
      ----------
      filename
          The filename.
      dtype
          Numpy data type.