Incorrect type check for `seg_len` in wfdb.MultiRecord.wrsamp

[JunPar]

The type check for the seg_len field in wfdb.MultiRecord.wrsamp is not functioning as documented.
According to the official documentation

https://wfdb.readthedocs.io/en/latest/wfdb.html#wfdb.MultiRecord

seg_len is described as having the type List[int].
However, using a list results in the following error:

TypeError: ('Field %s must be one of the following types:', (<class 'int'>, <class 'numpy.int64'>, <class 'numpy.int32'>, <class 'numpy.int16'>, <class 'numpy.int8'>))

Reviewing the source code confirms that the field is validated against integer types rather than a list:

# wfdb.io._header.py L118
SEGMENT_SPECS = pd.DataFrame(
    index=["seg_name", "seg_len"],
    columns=_SPECIFICATION_COLUMNS,
    dtype="object",
    data=[
        [(str), "", None, True, None, None],  # seg_name
        [int_types, " ", "seg_name", True, None, None],  # seg_len
    ],
)

This indicates that the implementation enforces seg_len as a single integer rather than a list of integers, which contradicts the documentation.

[dg4271]

It has been fixed in #514 and should work fine in versions 4.2.0 and later.