'Sets self.base_prompt
Used as delimiter for stripping of trailing prompt in output.
Should be set to something that is general and applies in multiple contexts. For Cisco
devices this will be set to router hostname (i.e. prompt without \'>\' or \'#\').
This will be set on entering user exec or privileged exec on Cisco, but not when
entering/exiting config mode.'

def set_base_prompt(self, pri_prompt_terminator=u'#', alt_prompt_terminator=u'>', delay_factor=1):

    prompt = self.find_prompt(delay_factor=delay_factor)
    if (not (prompt[(-1)] in (pri_prompt_terminator, alt_prompt_terminator))):
        raise ValueError(u'Router    prompt    not    found:    {0}'.format(prompt))
    self.base_prompt = prompt[:(-1)]
    return self.base_prompt
