code: public Variable getVariable(String name) {
          Variable result = find(name);
          if (result != null) {
              return result;
          }
          if (!autocreateVariables) {
              throw new IllegalArgumentException();
          }
  
          return create(name);
      }
docs: Searches for or creates a variable with the given name.
  <p>
  If no variable with the given name is found, a new variable is created in this scope
  
  @param name the variable to look for
  @return a variable with the given name
  @throws IllegalArgumentException if {@link #autocreateVariables} is <tt>false</tt> and the given
  variable was not creted yet.