@Nullable
 private PyType resolveQualifierType(
     @NotNull List<Token<PyElementType>> tokens,
     @NotNull PyFile file,
     @NotNull TypeEvalContext context,
     @NotNull Map<TextRange, PyType> types,
     @NotNull Map<PyType, TextRange> fullRanges,
     @NotNull Map<PyType, PyImportElement> imports) {
   if (tokens.isEmpty()) {
     return null;
   }
   final Token<PyElementType> firstToken = tokens.get(0);
   final String firstText = firstToken.getText().toString();
   final TextRange firstRange = firstToken.getRange();
   final List<RatedResolveResult> resolveResults = file.multiResolveName(firstText);
   if (resolveResults.isEmpty()) {
     return getImplicitlyResolvedType(tokens, context, types, fullRanges, firstRange);
   }
   final List<PyType> members = Lists.newArrayList();
   for (RatedResolveResult result : resolveResults) {
     final PsiElement resolved = result.getElement();
     PyType type = null;
     if (resolved instanceof PyTargetExpression) {
       type =
           PyTypingTypeProvider.getTypeFromTargetExpression(
               (PyTargetExpression) resolved, context);
     }
     if (type == null && resolved instanceof PyTypedElement) {
       type = context.getType((PyTypedElement) resolved);
     }
     if (type != null) {
       if (!allowResolveToType(type)) {
         continue;
       }
       if (type instanceof PyClassLikeType) {
         type = ((PyClassLikeType) type).toInstance();
       }
       types.put(firstRange, type);
       fullRanges.put(type, firstRange);
       for (PyFromImportStatement fromImportStatement : file.getFromImports()) {
         for (PyImportElement importElement : fromImportStatement.getImportElements()) {
           if (firstText.equals(importElement.getVisibleName())) {
             imports.put(type, importElement);
           }
         }
       }
       for (PyImportElement importElement : file.getImportTargets()) {
         if (firstText.equals(importElement.getVisibleName())) {
           imports.put(type, importElement);
         }
       }
     }
     members.add(type);
   }
   if (!members.isEmpty()) {
     tokens.remove(0);
   }
   return PyUnionType.union(members);
 }
  /** @param anchor should never be null or null will be returned */
  @NotNull
  public static ParseResult parse(@Nullable final PsiElement anchor, @NotNull String type) {
    PyPsiUtils.assertValid(anchor);
    if (anchor == null) {
      return EMPTY_RESULT;
    }

    final ForwardDeclaration<ParseResult, PyElementType> typeExpr = ForwardDeclaration.create();

    final FunctionalParser<ParseResult, PyElementType> classType =
        token(IDENTIFIER)
            .then(many(op(".").skipThen(token(IDENTIFIER))))
            .map(new MakeSimpleType(anchor))
            .cached()
            .named("class-type");

    final FunctionalParser<ParseResult, PyElementType> tupleType =
        op("(")
            .skipThen(typeExpr)
            .then(many(op(",").skipThen(typeExpr)))
            .thenSkip(op(")"))
            .map(
                value -> {
                  ParseResult result = value.getFirst();
                  final List<ParseResult> rest = value.getSecond();
                  if (rest.isEmpty()) {
                    return result;
                  }
                  final List<PyType> types = new ArrayList<>();
                  types.add(result.getType());
                  for (ParseResult r : rest) {
                    result = result.merge(r);
                    types.add(r.getType());
                  }
                  return result.withType(PyTupleType.create(anchor, types));
                })
            .named("tuple-type");

    final FunctionalParser<ParseResult, PyElementType> typeParameter =
        token(PARAMETER)
            .then(maybe(op("<=").skipThen(typeExpr)))
            .map(
                value -> {
                  final Token<PyElementType> token = value.getFirst();
                  final String name = token.getText().toString();
                  final TextRange range = token.getRange();
                  final ParseResult boundResult = value.getSecond();
                  if (boundResult != null) {
                    final PyGenericType type1 = new PyGenericType(name, boundResult.getType());
                    final ParseResult result = new ParseResult(null, type1, range);
                    return result.merge(boundResult).withType(type1);
                  }
                  return new ParseResult(null, new PyGenericType(name, null), range);
                })
            .named("type-parameter");

    final FunctionalParser<ParseResult, PyElementType> simpleExpr =
        classType.or(tupleType).or(typeParameter).named("simple-expr");

    final FunctionalParser<ParseResult, PyElementType> paramExpr =
        classType
            .thenSkip(op("["))
            .then(typeExpr)
            .then(many(op(",").skipThen(typeExpr)))
            .thenSkip(op("]"))
            .map(
                value -> {
                  final Pair<ParseResult, ParseResult> firstPair = value.getFirst();
                  final ParseResult first = firstPair.getFirst();
                  final ParseResult second = firstPair.getSecond();
                  final List<ParseResult> third = value.getSecond();
                  final PyType firstType = first.getType();
                  final List<PyType> typesInBrackets = new ArrayList<>();
                  typesInBrackets.add(second.getType());
                  ParseResult result = first;
                  result = result.merge(second);
                  for (ParseResult r : third) {
                    typesInBrackets.add(r.getType());
                    result = result.merge(r);
                  }
                  final List<PyType> elementTypes =
                      third.isEmpty()
                          ? Collections.singletonList(second.getType())
                          : typesInBrackets;
                  final PsiElement resolved = first.getElement();
                  if (resolved != null) {
                    final PyType typingType = PyTypingTypeProvider.getType(resolved, elementTypes);
                    if (typingType != null) {
                      return result.withType(typingType);
                    }
                  }
                  if (firstType instanceof PyClassType) {
                    final PyType type1 =
                        new PyCollectionTypeImpl(
                            ((PyClassType) firstType).getPyClass(), false, elementTypes);
                    return result.withType(type1);
                  }
                  return EMPTY_RESULT;
                })
            .or(
                classType
                    .thenSkip(op("of"))
                    .then(simpleExpr)
                    .map(
                        value -> {
                          final ParseResult firstResult = value.getFirst();
                          final ParseResult secondResult = value.getSecond();
                          final ParseResult result = firstResult.merge(secondResult);
                          final PyType firstType = firstResult.getType();
                          final PyType secondType = secondResult.getType();
                          if (firstType != null) {
                            if (firstType instanceof PyClassType && secondType != null) {
                              return result.withType(
                                  new PyCollectionTypeImpl(
                                      ((PyClassType) firstType).getPyClass(),
                                      false,
                                      Collections.singletonList(secondType)));
                            }
                            return result.withType(firstType);
                          }
                          return EMPTY_RESULT;
                        }))
            .or(
                classType
                    .thenSkip(op("from"))
                    .then(simpleExpr)
                    .thenSkip(op("to"))
                    .then(simpleExpr)
                    .map(
                        value -> {
                          final Pair<ParseResult, ParseResult> firstPair = value.getFirst();
                          final ParseResult first = firstPair.getFirst();
                          final ParseResult second = firstPair.getSecond();
                          final ParseResult third = value.getSecond();
                          final PyType firstType = first.getType();
                          if (firstType instanceof PyClassType) {
                            final List<PyType> elementTypes =
                                Arrays.asList(second.getType(), third.getType());
                            final PyCollectionTypeImpl type1 =
                                new PyCollectionTypeImpl(
                                    ((PyClassType) firstType).getPyClass(), false, elementTypes);
                            return first.merge(second).merge(third).withType(type1);
                          }
                          return EMPTY_RESULT;
                        }))
            .named("param-expr");

    final FunctionalParser<ParseResult, PyElementType> callableExpr =
        op("(")
            .skipThen(maybe(typeExpr.then(many(op(",").skipThen(typeExpr)))))
            .thenSkip(op(")"))
            .thenSkip(op("->"))
            .then(typeExpr)
            .map(
                value -> {
                  final List<PyCallableParameter> parameters = new ArrayList<>();
                  final ParseResult returnResult = value.getSecond();
                  ParseResult result;
                  final Pair<ParseResult, List<ParseResult>> firstPair = value.getFirst();
                  if (firstPair != null) {
                    final ParseResult first = firstPair.getFirst();
                    final List<ParseResult> second = firstPair.getSecond();
                    result = first;
                    parameters.add(new PyCallableParameterImpl(null, first.getType()));
                    for (ParseResult r : second) {
                      result = result.merge(r);
                      parameters.add(new PyCallableParameterImpl(null, r.getType()));
                    }
                    result = result.merge(returnResult);
                  } else {
                    result = returnResult;
                  }
                  return result.withType(
                      new PyCallableTypeImpl(parameters, returnResult.getType()));
                })
            .named("callable-expr");

    final FunctionalParser<ParseResult, PyElementType> singleExpr =
        paramExpr.or(callableExpr).or(simpleExpr).named("single-expr");

    final FunctionalParser<ParseResult, PyElementType> unionExpr =
        singleExpr
            .then(many(op("or").or(op("|")).skipThen(singleExpr)))
            .map(
                value -> {
                  final ParseResult first = value.getFirst();
                  final List<ParseResult> rest = value.getSecond();
                  if (rest.isEmpty()) {
                    return first;
                  }
                  final List<PyType> types = new ArrayList<>();
                  types.add(first.getType());
                  ParseResult result = first;
                  for (ParseResult r : rest) {
                    types.add(r.getType());
                    result = result.merge(r);
                  }
                  return result.withType(PyUnionType.union(types));
                })
            .named("union-expr");

    typeExpr.define(unionExpr).named("type-expr");

    final FunctionalParser<ParseResult, PyElementType> typeFile =
        typeExpr.endOfInput().named("type-file");

    try {
      return typeFile.parse(tokenize(type));
    } catch (ParserException e) {
      return EMPTY_RESULT;
    }
  }