code: public boolean hasRoleGrant(Grant grant,String role){
          if (grant == null) throw new IllegalArgumentException("grant cannot be null");
          if (role == null) throw new IllegalArgumentException("role cannot be null");
          Set<String> roles = rolesGrants.get(grant);
          return roles!=null&&roles.contains(role);
      }
docs: Checks if the role has the specified {@code grant}
  @param grant a {@link com.baasbox.android.Grant}
  @param role a role
  @return