code: def apt(self, package_names, raise_on_error=False):
          
          if isinstance(package_names, basestring):
              package_names = [package_names]
          cmd = "apt-get install -y %s" % (' '.join(package_names))
          return self.wait(cmd, raise_on_error=raise_on_error)
docs: Install specified packages using apt-get. -y options are
          automatically used. Waits for command to finish.
  
          Parameters
          ----------
          package_names: list-like of str
          raise_on_error: bool, default False
              If True then raise ValueError if stderr is not empty
              debconf often gives tty error