code: public OpDef getOpDefByTensorflowName(String name) {
          if(!tensorflowOpDescriptors.containsKey(name)) {
              throw new ND4JIllegalStateException("No op found with name " + name);
          }
  
          return tensorflowOpDescriptors.get(name);
      }
docs: Get the op definition of a given
  tensorflow op.
  
  Note that if the name does not exist,
  an {@link ND4JIllegalStateException} will be thrown
  @param name the name of the op
  @return the op definition for a given op