How to get line breaks in e-mail sent using Python's smtplib?

I have written a script that writes a message to a text file and also sends it as an email. Everything goes well, except the email finally appears to be all in one line.

I add line breaks by \n and it works for the text file but not for the email. Do you know what could be the possible reason?

Here's my code:

import smtplib, sys
import traceback
def send_error(sender, recipient, headers, body):

    SMTP_SERVER = 'smtp.gmail.com'
    SMTP_PORT = 587
    session = smtplib.SMTP('smtp.gmail.com', 587)
    session.ehlo()
    session.starttls()
    session.ehlo
    session.login(sender, 'my password')
    send_it = session.sendmail(sender, recipient, headers + "\r\n\r\n" +  body)
    session.quit()
    return send_it


SMTP_SERVER = 'smtp.gmail.com'
SMTP_PORT = 587
sender = 'sender_id@gmail.com'
recipient = 'recipient_id@yahoo.com'
subject = 'report'
body = "Dear Student, \n Please send your report\n Thank you for your attention"
open('student.txt', 'w').write(body) 

headers = ["From: " + sender,
               "Subject: " + subject,
               "To: " + recipient,
               "MIME-Version: 1.0",
               "Content-Type: text/html"]
headers = "\r\n".join(headers)
send_error(sender, recipient, headers, body)

You have your message body declared to have HTML content ("Content-Type: text/html"). The HTML code for line break is <br>. You should either change your content type to text/plain or use the HTML markup for line breaks instead of plain \n as the latter gets ignored when rendering a HTML document.

As a side note, also have a look at the email package. There are some classes that can simplify the definition of E-Mail messages for you (with examples).

For example you could try (untested):

import smtplib
from email.mime.text import MIMEText

# define content
recipients = ["recipient_id@yahoo.com"]
sender = "sender_id@gmail.com"
subject = "report reminder"
body = """
Dear Student,
Please send your report
Thank you for your attention
"""

# make up message
msg = MIMEText(body)
msg['Subject'] = subject
msg['From'] = sender
msg['To'] = ", ".join(recipients)

# sending
session = smtplib.SMTP('smtp.gmail.com', 587)
session.starttls()
session.login(sender, 'my password')
send_it = session.sendmail(sender, recipients, msg.as_string())
session.quit()