<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get(self, key, prompt_default='', prompt_help=''):
 """Return a value from the environ or keyring"""

        value = os.getenv(key)
        if not value:
            ns = self.namespace(key)
            value = self.keyring.get_password(ns, key)
        else:
            ns = 'environ'  
        if not value:
            ns = self.namespace(key, glob=True)
            value = self.keyring.get_password(ns, key)
        if not value:
            ns = ''
        if not value and self.prompt:
            value = self._prompt_for_value(key, prompt_default, prompt_help)
            if value:
                self.set(key, value)
        if ns:
            self.kns[key] = ns
        return value