How to use the cython.test_assert_path_exists function in Cython

@cython.test_assert_path_exists('//PythonCapiCallNode')
@cython.locals(d=dict)
def setdefault2(d, key, value):
    """
    >>> d = {}
    >>> setdefault2(d, 1, 2)
    2
    >>> len(d)
    1
    >>> setdefault2(d, 1, 2)
    2
    >>> len(d)
    1
    >>> l = setdefault2(d, 2, [])
    >>> len(d)
    2
    >>> l.append(1)

@cython.test_assert_path_exists(
    "//BoolNode",
)
@cython.test_fail_if_path_exists(
    "//PrimaryCmpNode",
    "//MulNode",
    "//ListNode//IntNode",
)
def combined():
    """
    >>> combined()
    True
    """
    return 5 in 100 * [1, 2] * 0  or  5 not in 100 * [] * 10

@cython.test_assert_path_exists(
    "//BoolNode",
)
@cython.test_fail_if_path_exists(
    "//PrimaryCmpNode",
    "//MulNode",
    "//ListNode//IntNode",
)
def in_mult_list():
    """
    >>> in_mult_list()
    False
    """
    return 5 in 100 * [1, 2] * 0

@cython.test_assert_path_exists("//CFuncDeclaratorNode//IntNode[@value = '-1']")
@cython.cfunc
@cython.returns(cython.long)
@cython.exceptval(-1)
def cdef_except(x):
    if x == 0:
        raise ValueError
    return x+1

@cython.test_assert_path_exists(
    '//IntNode[@value = "2"]',
    '//IntNode[@value = "4"]',
    '//IntNode[@value = "5"]',
    '//IntNode[@value = "7"]',
    '//BoolBinopNode//PrimaryCmpNode',
    '//BoolBinopNode[.//PrimaryCmpNode//IntNode[@value = "4"] and .//PrimaryCmpNode//IntNode[@value = "5"]]',
    '//PrimaryCmpNode[.//IntNode[@value = "2"] and .//IntNode[@value = "4"]]',
    '//PrimaryCmpNode[.//IntNode[@value = "5"] and .//IntNode[@value = "7"]]',
)
@cython.test_fail_if_path_exists(
    '//IntNode[@value = "1"]',
    '//IntNode[@value = "8"]',
    '//PrimaryCmpNode[.//IntNode[@value = "4"] and .//IntNode[@value = "5"]]',
    '//PrimaryCmpNode[.//IntNode[@value = "2"] and .//IntNode[@value = "7"]]',
    '//BoolNode',
)

@cython.test_assert_path_exists('//PythonCapiCallNode')
@cython.locals(d=dict)
def setdefault1(d, key):
    """
    >>> d = {}
    >>> setdefault1(d, 1)
    >>> len(d)
    1
    >>> setdefault1(d, 1)
    >>> len(d)
    1
    >>> d[1]
    >>> setdefault1(d, Unhashable())
    Traceback (most recent call last):
    TypeError: I am not hashable
    >>> len(d)
    1

@cython.test_assert_path_exists('//SimpleCallNode[@function.type.is_cfunction = True]')
@cython.test_fail_if_path_exists('//SimpleCallNode[@function.type.is_builtin_type = True]')
def call_str(arg):
    """
    >>> print(call_str('TEST'))
    STR
    """
    return str(arg)

@cython.test_assert_path_exists("//CFuncDeclaratorNode//IntNode[@value = '-1']")
@cython.ccall
@cython.returns(cython.long)
@cython.exceptval(-1)
def ccall_except(x):
    """
    >>> ccall_except(41)
    42
    >>> ccall_except(0)
    Traceback (most recent call last):
    ValueError
    """
    if x == 0:
        raise ValueError
    return x+1

@cython.test_assert_path_exists('//ReturnStatNode//ForInStatNode//TupleNode')
@cython.test_fail_if_path_exists('//ReturnStatNode//ForInStatNode//ListNode')
def listcomp_over_multiplied_constant_list():
    """
    >>> listcomp_over_multiplied_constant_list()
    [[], [1, 2, 3], [1, 2, 3, 1, 2, 3], [1, 2, 3, 1, 2, 3, 1, 2, 3], [1, 2, 3, 1, 2, 3]]
    """
    return [
        [i for i in [1, 2, 3] * 0],
        [i for i in [1, 2, 3] * 1],
        [i for i in [1, 2, 3] * 2],
        [i for i in [1, 2, 3] * 3],
        [i for i in [1, 2, 3] * 2],
    ]

@cython.test_assert_path_exists("//CFuncDeclaratorNode//IntNode[@value = '-1']")
@cython.ccall
@cython.returns(cython.long)
@cython.exceptval(-1, check=True)
def ccall_except_check(x):
    """
    >>> ccall_except_check(41)
    42
    >>> ccall_except_check(-2)
    -1
    >>> ccall_except_check(0)
    Traceback (most recent call last):
    ValueError
    """
    if x == 0:
        raise ValueError
    return x+1