code: func (c *Client) ApplyFirewallPolicy(policyId string, serverGroupId string) (*FirewallPolicy, error) {
  	policy := new(FirewallPolicy)
  	_, err := c.MakeApiRequest("POST", "/1.0/firewall_policies/"+policyId+"/apply_to",
  		map[string]string{"server_group": serverGroupId}, &policy)
  	if err != nil {
  		return nil, err
  	}
  	return policy, nil
  }
docs: // ApplyFirewallPolicy issues a request to apply the given firewall policy to
  // the given server group.
  //