private @Nullable DependencyRule readRule(@NotNull Element ruleElement) {
    String fromScope = ruleElement.getAttributeValue(FROM_SCOPE_KEY);
    String toScope = ruleElement.getAttributeValue(TO_SCOPE_KEY);
    String denyRule = ruleElement.getAttributeValue(IS_DENY_KEY);
    if (fromScope == null || toScope == null || denyRule == null) return null;
    final NamedScope fromNamedScope = getScope(fromScope);
    final NamedScope toNamedScope = getScope(toScope);
    if (fromNamedScope == null || toNamedScope == null) return null;
    return new DependencyRule(fromNamedScope, toNamedScope, Boolean.valueOf(denyRule).booleanValue());
  }
private @Nullable DependencyRule readRule(@NotNull Element ruleElement)