Achange attachments from mail message object

In Python, when working with email messages using the email module, you can access and modify attachments using the attachments attribute of the Message object.

Here's an example:

import email
from email.mime.multipart import MIMEMultipart
from email.mime.base import MIMEBase
from email.mime.text import MIMEText

# Create a new email message
msg = MIMEMultipart()

# Add a text body
msg.attach(MIMEText("Hello, world!", "plain"))

# Add an attachment
attachment = MIMEBase("application", "octet-stream")
attachment.set_payload(b"Hello, world!")
msg.attach(attachment)

# Print the attachments
print(msg.get_payload())

# Change the attachment
attachment = msg.get_payload()[1]  # Get the second attachment (index 1)
attachment.set_payload(b"Goodbye, world!")
msg.attach(attachment)

# Print the updated attachments
print(msg.get_payload())

In this example, we create a new email message with a text body and an attachment. We then print the attachments using the get_payload() method, which returns a list of Message objects representing the attachments.

To change an attachment, we get the attachment object using the get_payload() method and modify its payload using the set_payload() method. We then re-attach the modified attachment to the message using the attach() method.

Note that the get_payload() method returns a list of Message objects, so we need to access the attachment object using its index (in this case, index 1, since the text body is the first attachment).

Also, be aware that modifying attachments can be complex and may require additional processing, such as updating the attachment's content type or encoding.