code: func (c *Client) IsTeamMember(teamID, token string) (bool, error) {
  	u, err := c.GetUser(token)
  	if err != nil {
  		return false, err
  	}
  
  	req, err := c.NewRequest("GET", fmt.Sprintf("/teams/%s/memberships/%s", teamID, u.Login), nil)
  	if err != nil {
  		return false, err
  	}
  
  	tokenAuth(req, token)
  
  	var t TeamMembership
  
  	resp, err := c.Do(req, &t)
  	if err != nil {
  		if resp != nil && resp.StatusCode == 404 {
  			return false, nil
  		}
  		return false, err
  	}
  
  	return t.State == "active", nil
  }
docs: // IsTeamMember returns true if the given user is a member of the team.