code: public BaiduMessage withSubstitutions(java.util.Map<String, java.util.List<String>> substitutions) {
          setSubstitutions(substitutions);
          return this;
      }
docs: Default message substitutions. Can be overridden by individual address substitutions.
  
  @param substitutions
  Default message substitutions. Can be overridden by individual address substitutions.
  @return Returns a reference to this object so that method calls can be chained together.