from robobrowser import RoboBrowser
browser = RoboBrowser(parser='lxml')
browser.open('http://flymer.ru/signup')

form = browser.get_form('signup')
form['email'].value = 'vasya12343242323@inbox.ru'
form['pass'].value = '123456'
form['agree'].value = '1'

browser.submit_form(form)

print(browser.response.text)  # {"ok":1}