How to get href from class in python

I want to get href from a = soup.find_all('div', class_='email-messages'). `

[<div class="email-messages">
<table>
<tr>
<td id="email-title">Message Title</td>
<td id="email-sender">Sender</td>
<td id="email-control">Control </td>
</tr>
<tr>
<td><a href="/en/msg/3EEB344D-505C-8CE7-09C5-2DD54F1AECD1">Fwd: [Microsoft Academic Verification] Confirming Your Academic Status</a></td>
<td id="email-sender"><span data-cf-modified-c9b86b506f187bfdc48368eb-="" onclick="if (!window.__cfRLUnblockHandlers) return false; show_sender_email(this, 'guidetuanhp@gmail.com')" style="cursor: pointer;">Tuấn Anh Vũ</span></td>
<td id="email-control"><a data-cf-modified-c9b86b506f187bfdc48368eb-="" href="/en/msg/3EEB344D-505C-8CE7-09C5-2DD54F1AECD1/delete" onclick="if (!window.__cfRLUnblockHandlers) return false; return delete_mail('/msg/3EEB344D-505C-8CE7-09C5-2DD54F1AECD1/delete');">[Delete]</a></td>
</tr>
<tr>
<td class="mail_message_counter" colspan="3">Total Messages: <strong>1</strong></td>
</tr>
</table>
</div>]

` My code:

soup = BeautifulSoup(html_doc, 'lxml')
a = soup.find_all('div', class_='email-messages')
for link in a:
    print(link['href'])

I got error: in getitem return self.attrs[key] KeyError: 'href'

Can you help me check this?