Add headers to email attachments

Example usage:
    def find_attachment_by_cid(cid: str) -> Attachment | None:
        for att in message.attachments:
            for header in att.headers:
                if header['name'] == 'Content-ID' and header['value'] == f'<{cid}>':
                    return att

Signed-off-by: Blaz Primc <[email protected]>

simplegmail/attachment.py

@@ -7,7 +7,7 @@
 
 import base64  # for base64.urlsafe_b64decode
 import os      # for os.path.exists
-from typing import Optional
+from typing import Optional, List, Dict
 
 class Attachment(object):
     """
@@ -21,6 +21,7 @@ class should not be manually instantiated.
         att_id: The id of the attachment.
         filename: The filename associated with the attachment.
         filetype: The mime type of the file.
+        headers: The headers of the attachment.
         data: The raw data of the file. Default None.
 
     Attributes:
@@ -30,6 +31,7 @@ class should not be manually instantiated.
         id (str): The id of the attachment.
         filename (str): The filename associated with the attachment.
         filetype (str): The mime type of the file.
+        headers: The headers of the attachment.
         data (bytes): The raw data of the file.
 
     """
@@ -42,6 +44,7 @@ def __init__(
         att_id: str,
         filename: str,
         filetype: str,
+        headers: Optional[List[Dict]],
         data: Optional[bytes] = None
     ) -> None:
         self._service = service
@@ -50,6 +53,7 @@ def __init__(
         self.id = att_id
         self.filename = filename
         self.filetype = filetype
+        self.headers = headers or []
         self.data = data
 
     def download(self) -> None:

simplegmail/gmail.py

@@ -826,7 +826,7 @@ def _build_message_from_ref(
                 elif part['part_type'] == 'attachment':
                     attm = Attachment(self.service, user_id, msg_id,
                                       part['attachment_id'], part['filename'],
-                                      part['filetype'], part['data'])
+                                      part['filetype'], part['headers'], part['data'])
                     attms.append(attm)
 
             return Message(
@@ -892,6 +892,7 @@ def _evaluate_message_payload(
                 'filetype': payload['mimeType'],
                 'filename': filename,
                 'attachment_id': att_id,
+                'headers': payload['headers'],
                 'data': None
             }