rulebook-core/src/main/java/com/deliveredtechnologies/rulebook/StandardRule.java
@Override
  @SuppressWarnings("unchecked")
  public Rule<T> given(Fact<T>... facts) {
    for (Fact f : facts) {
      _facts.put(f.getName(), f);
    }

    return this;
  }
@Override
  @SuppressWarnings("unchecked")
  public Rule<T> given(Fact<T>... facts) {
    for (Fact f : facts) {
      _facts.put(f.getName(), f);
    }

    return this;
  }
The given() method accepts Facts to be evaluated in the Rule.
@param facts Facts to be used by the Rule
@return      the current object