def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def run(self):
    hdrs = self.distribution.headers
    if not hdrs:
      return

    self.mkpath(self.install_dir)
    for header in hdrs:
      (out, _) = self.mkdir_and_copy_file(header)
      self.outfiles.append(out)