code: public void setSubnetMappings(java.util.Collection<SubnetMapping> subnetMappings) {
          if (subnetMappings == null) {
              this.subnetMappings = null;
              return;
          }
  
          this.subnetMappings = new java.util.ArrayList<SubnetMapping>(subnetMappings);
      }
docs: <p>
  The IDs of the public subnets. You must specify subnets from at least two Availability Zones. You can specify
  only one subnet per Availability Zone. You must specify either subnets or subnet mappings.
  </p>
  <p>
  You cannot specify Elastic IP addresses for your subnets.
  </p>
  
  @param subnetMappings
  The IDs of the public subnets. You must specify subnets from at least two Availability Zones. You can
  specify only one subnet per Availability Zone. You must specify either subnets or subnet mappings.</p>
  <p>
  You cannot specify Elastic IP addresses for your subnets.