Whether the condition contains the specified values.

    Args:
      artifact: A string identifier for the artifact.
      os_name: An OS string.
      cpe: A CPE string.
      label: A label string.

    Returns:
      True if the values match the non-empty query attributes.
      Empty query attributes are ignored in the comparison.

def Search(self, artifact, os_name=None, cpe=None, label=None):
    """Whether the condition contains the specified values.

    Args:
      artifact: A string identifier for the artifact.
      os_name: An OS string.
      cpe: A CPE string.
      label: A label string.

    Returns:
      True if the values match the non-empty query attributes.
      Empty query attributes are ignored in the comparison.
    """
    hit = lambda x: x[0] == x[1] or not x[0]
    seq = [(artifact, self.artifact), (os_name, self.os_name), (cpe, self.cpe),
           (label, self.label)]
    return all(map(hit, seq))