Reader class attributes immutable (Cannot edit "sample_id" field of mutable read object)

[jennifergribble-nanopore]

Issue Description

I have installed the pod5 package via pip and were attempting to use it via a custom Python script as referenced in this issue:

https://github.com/nanoporetech/pod5-file-format/issues/100

to edit the sample_id field. The error is:

Exception has occurred: FrozenInstanceError
cannot assign to field 'sample_id'
File "/data/TS_data_analysis/jgribble/abrf_methylation/pod5_rename/pod5_rename_test.py", line 12, in
read.run_info.sample_id = str('NA24385_MGI_Lib1_New_flowcell')
^^^^^^^^^^^^^^^^^^^^^^^
dataclasses.FrozenInstanceError: cannot assign to field 'sample_id'

To my understanding, this appears that the following code block does not create a mutable RunInfo attribute? Is this intended or should users be able to edit RunInfo fields using this package?

import pod5

# New output file for edited data
with pod5.Writer("output.pod5") as writer:
    # Read all records
    with pod5.Reader("input.pod5") as reader:
          # Iterate over immutable ReadRecords
          for record in reader:
               # Convert to mutable Read
               read = record.to_read()
               # Edit the value
               read.run_info.sample_id = str('NA24385_MGI_Lib1_New_flowcell')

Specifications

• Pod5 Version: 0.3.6
• Python Version: 3.11
• Platform: conda env on Linux (Ubuntu 20.04)

[HalfPhoton]

Hi @jennifergribble-nanopore,
One must assign a new RunInfo instance to replace the existing immutable one.

from copy import deepcopy
run_info = vars(deepcopy(read.run_info))
run_info["sample_id"] = str('NA24385_MGI_Lib1_New_flowcell')
read.run_info = pod5.RunInfo(**run_info)

Kind regards,
Rich