'Create a new instance of PlainCredentials
:param str username: The username to authenticate with
:param str password: The password to authenticate with
:param bool erase_on_connect: erase credentials on connect.'

def __init__(self, username, password, erase_on_connect=False):

    self.username = username
    self.password = password
    self.erase_on_connect = erase_on_connect
