code: public GetContextKeysForPrincipalPolicyResult withContextKeyNames(String... contextKeyNames) {
          if (this.contextKeyNames == null) {
              setContextKeyNames(new com.amazonaws.internal.SdkInternalList<String>(contextKeyNames.length));
          }
          for (String ele : contextKeyNames) {
              this.contextKeyNames.add(ele);
          }
          return this;
      }
docs: <p>
  The list of context keys that are referenced in the input policies.
  </p>
  <p>
  <b>NOTE:</b> This method appends the values to the existing list (if any). Use
  {@link #setContextKeyNames(java.util.Collection)} or {@link #withContextKeyNames(java.util.Collection)} if you
  want to override the existing values.
  </p>
  
  @param contextKeyNames
  The list of context keys that are referenced in the input policies.
  @return Returns a reference to this object so that method calls can be chained together.