def main(ctx):
    which = "where" if sys.platform == "win32" else "which"
    if envoy.run(which + " git").status_code != 0:
        click.secho("fatal: git not found in PATH", fg="red")
        sys.exit(1)
    ctx.obj = Hydrogen()
def gradients(self, d_grads, g_grads):
      if self.d_grads is None:
          self.d_grads = [torch.zeros_like(_g) for _g in d_grads]
          self.g_grads = [torch.zeros_like(_g) for _g in g_grads]