code: public FaunusPipeline interval(final String key, final Object startValue, final Object endValue) {
          this.state.assertNotLocked();
          this.state.assertNoProperty();
  
          this.compiler.addMap(IntervalFilterMap.Map.class,
                  NullWritable.class,
                  FaunusVertex.class,
                  IntervalFilterMap.createConfiguration(this.state.getElementType(), key, startValue, endValue));
          makeMapReduceString(IntervalFilterMap.class, key, startValue, endValue);
          return this;
      }
docs: Emit the current element it has a property value equal within the provided range.
  
  @param key        the property key of the element
  @param startValue the start of the range (inclusive)
  @param endValue   the end of the range (exclusive)
  @return the extended FaunusPipeline