<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _GenNetflowRecordV9(cls, lengths_list):
 """Internal function used to generate the Records from their template. """

    _fields_desc = []
    for j, k in lengths_list:
        _f_data = NetflowV9TemplateFieldDecoders.get(k, None)
        _f_type, _f_args = (
            _f_data if isinstance(_f_data, tuple) else (_f_data, [])
        )
        _f_kwargs = {}
        if _f_type:
            if issubclass(_f_type, _AdjustableNetflowField):
                _f_kwargs["length"] = j
            _fields_desc.append(
                _f_type(
                    NetflowV910TemplateFieldTypes.get(k, "unknown_data"),
                    0, *_f_args, **_f_kwargs
                )
            )
        else:
            _fields_desc.append(
                _CustomStrFixedLenField(
                    NetflowV910TemplateFieldTypes.get(k, "unknown_data"),
                    b"", length=j
                )
            )

    # This will act exactly like a NetflowRecordV9, but has custom fields
    class NetflowRecordV9I(cls):
        fields_desc = _fields_desc
        match_subclass = True
    NetflowRecordV9I.name = cls.name
    NetflowRecordV9I.__name__ = cls.__name__
    return NetflowRecordV9I