Construction of smtp client

    def send_mail(self,cr,uid,ids,to=[],cc=[],bcc=[],subject="",body_text="",body_html="",payload={}):
        #ids:(from) Account from which mail is to be sent
        #to: To ids as list
        #cc: CC ids as list
        #bcc: BCC ids as list
        #subject: Subject as string
        #body_text: body as plain text
        #body_html: body in html
        #payload: attachments as binary dic. Eg:payload={'filename1.pdf':<binary>,'filename2.jpg':<binary>}
To send a mail:

self.pool.get('poweremail.core_accounts').send_mail(cr,uid,acc_id,[to],[cc],[bcc],"Subject",body_text,body_html,{})