code: public ImmutableList<InstanceInfo> getInstancesWithMetadata(Map<String, String> metadataQuery) {
          checkArgument(!checkNotNull(metadataQuery, "metadataQuery").isEmpty(), "No metadata query arguments specified");
          return getInstancesWithMetadataImpl(metadataQuery);        
      }
docs: Retrieve information about all online instances matching the given metadata query from the Conqueso Server.
  The metadata query is expressed as key/value pairs in the provided map. For example, calling this method like
  this:
  <p>
  <code>
  conquesoClient.getInstancesWithMetadata(ImmutableMap.of("availability-zone", "us-east-1c",
  "instance-type", "m1.small"));
  </code>
  </p>
  will return all instances with metadata that matches availability-zone=us-east-1c and instance-type=m1.small.
  
  @param metadataQuery the map key/value pairs representing a query for instances matching the metadata
  @return the information about the matching instances
  @throws ConquesoCommunicationException if there's an error communicating with the Conqueso Server.