How to use the h5netcdf.core.Group._create_dimension function in h5netcdf

dt = self._h5ds.dtype
        if h5py.check_dtype(vlen=dt) is unicode:
            return str
        return dt


class Group(core.Group, HasAttributesMixin):
    _cls_name = 'h5netcdf.legacyapi.Group'
    _variable_cls = Variable

    @property
    def _group_cls(self):
        return Group

    createGroup = core.Group.create_group
    createDimension = core.Group._create_dimension

    def createVariable(self, varname, datatype, dimensions=(), zlib=False,
                       complevel=4, shuffle=True, fletcher32=False,
                       chunksizes=None, fill_value=None):
        if len(dimensions) == 0:  # it's a scalar
            # rip off chunk and filter options for consistency with netCDF4-python

            chunksizes = None
            zlib = False
            fletcher32 = False
            shuffle = False

        if datatype is str:
            datatype = h5py.special_dtype(vlen=unicode)

        kwds = {}