if args_to_set['position']:
        if len(np.shape(args_to_set['position'])) > 1 or \
        (len(np.shape(args_to_set['position'])) == 1 and len(args_to_set['position']) != 3):
            raise ValueError(f"ElectrodeGroup position argument must have three elements: x, y, z,"
                            f"but received: {args_to_set['position']}")
        else:
            args_to_set['position'] = np.array(args_to_set['position'], dtype=[('x', float), ('y', float), ('z', float)])

from pynwb import NWBFile, NWBHDF5IO
from uuid import uuid4
from datetime import datetime

nwbfile = NWBFile(
    session_description="no description.",
    session_start_time=datetime.now(),
    identifier=str(uuid4()),
)

device = nwbfile.create_device(name="Device", description="no description.")

electrode_group = nwbfile.create_electrode_group(
    name="ElectrodeGroup",
    description="no description.",
    device=device,
    location="unknown",
    position=[(1., 2., 3.)],  # --> dataset shape = (1,)
    # position=(1, 2, 3)      # --> dataset shape = (3,)
)
)

with NWBHDF5IO('test.nwb', 'w') as io:
    io.write(nwbfile)
    
with NWBHDF5IO('test.nwb', 'r') as io:
    read_nwbfile = io.read()
    
    print(read_nwbfile.electrode_groups['ElectrodeGroup'].position.shape)  # (1,)