Receive emails with Python

I am trying to receive with Python the emails that I have in my Gmail. I connect without problems to my account and I get the mail from the one who sent the message, the subject or the delivery time, but there is no way to get the body of the message. I leave here my code and I explain:

import smtplib
import time
import imaplib
import email

def read_email_from_gmail():
try:
    mail = imaplib.IMAP4_SSL('imap.gmail.com')
    mail.login('[email protected]','micontraseña')
    mail.select('inbox')

    type, data = mail.search(None, 'ALL')
    mail_ids = data[0]

    id_list = mail_ids.split()   
    first_email_id = int(id_list[0])
    latest_email_id = int(id_list[-1])


    for i in range(latest_email_id,first_email_id, -1):
        typ, data = mail.fetch(i, '(RFC822)' )

        for response_part in data:
            if isinstance(response_part, tuple):
                msg = email.message_from_string(response_part[1])
                email_subject = msg['subject']
                email_from = msg['from']
                email_date = msg['Date']
                email_body = msg['body']
                print 'From : ' + email_from + '\n'
                print 'Subject : ' + email_subject + '\n'
                print 'Date : ' + email_date + '\n'
                print 'Body : ' + email_body + '\n'

except Exception, e:
   print "Exception"
read_email_from_gmail()

As you can see, for example, I get the date with msg['Date'] , but I do not get something that returns the body of the message. I've tried Body and main, and I can not think of anything else. Thanks in advance.

******** Update September 11 ************

I have updated the code as you told me, now I am closer, but still missing things.

import smtplib
import time
import imaplib
import email

def read_email_from_gmail():
    try:
        mail = imaplib.IMAP4_SSL('imap.gmail.com')
        mail.login('[email protected]','isurki2230')
        mail.select('inbox')

       type, data = mail.search(None, 'ALL')
       mail_ids = data[0]

       id_list = mail_ids.split()   
       first_email_id = int(id_list[0])
       latest_email_id = int(id_list[-1])


       for i in range(latest_email_id,first_email_id, -1):
           typ, data = mail.fetch(i, '(RFC822)' )

           for response_part in data:
                if isinstance(response_part, tuple):
                    msg = email.message_from_string(response_part[1])
                    if msg.is_multipart():
                        for part in msg.walk():       
                            if part.get_content_type() in ("text/plain",   "text/html"):
                                print(part.get_payload(decode = True))
                    else: 
                        print(part.get_payload(decode = True))


    except Exception, e:
       print "\n"
read_email_from_gmail()

With that code this is the output I get:

This is a test #Aqui shows me a strange square

This is a test
#Aqui the message appears again, but with several html things like div and br, but when writing it in StackOverflow they do not appear. Can the code be "cleaned" a little more? Thanks.