请问下，polars中iterator报错是因为什么，代码没改，甚至上午还运行成功了，下午就一直报这类错：

thread 'main' panicked at D:\my_programs\cargo_home\registry\src\index.crates.io-6f17d22bba15001f\polars-core-0.43.1\src\series\iterator.rs:88:9:
assertion `left == right` failed: impl error
  left: 8
 right: 1
stack backtrace:
   0: std::panicking::begin_panic_handler
             at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library\std\src\panicking.rs:665
   1: core::panicking::panic_fmt
             at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library\core\src\panicking.rs:74
   2: core::panicking::assert_failed_inner
             at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c/library\core\src\panicking.rs:405
   3: core::panicking::assert_failed<usize,usize>
             at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c\library\core\src\panicking.rs:365
   4: polars_core::series::Series::iter
             at D:\my_programs\cargo_home\registry\src\index.crates.io-6f17d22bba15001f\polars-core-0.43.1\src\series\iterator.rs:88
   5: test_20250212::write_to_excel
             at .\src\main.rs:149
   6: test_20250212::main
             at .\src\main.rs:57
   7: core::ops::function::FnOnce::call_once<enum2$<core::result::Result<tuple$<>,alloc::boxed::Box<dyn$<core::error::Error>,alloc::alloc::Global> > > (*)(),tuple$<> >
             at /rustc/eeb90cda1969383f56a2637cbd3037bdf598841c\library\core\src\ops\function.rs:250
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
error: process didn't exit successfully: `E:\work_using_apps\cargo_target_dir\debug\test_20250212.exe` (exit code: 101)

报错相关代码如下：

    for (col_idx, col_series) in df_matched.collect()?.get_columns().iter().enumerate() {
        for (row_idx, data) in col_series.iter().enumerate() {   <= 本行报错
            println!("row_idx is {}, col_idx is {}, data is {}", row_idx, col_idx, data.to_string());;
        }
    }

• 其中，df_matched可以通过println!宏打印出来：df_matched is shape: (10_424, 12)，但是就是无法通过上面那个二重循环遍历（明明早上还好好的，啊啊啊！！！！）