<p>尝试执行以下操作时:</p>
<pre><code>for line in blines:
line.account = get_customer(line.AccountCode)
</code></pre>
<p>试图将值赋给<code>line.account</code>时出现错误:</p>
<pre><code>DetachedInstanceError: Parent instance <SunLedgerA at 0x16eda4d0> is not bound to a Session; lazy load operation of attribute 'account' cannot proceed
</code></pre>
<p>我做错什么了吗??</p>