How to use the tablib.packages.yaml.constructor.ConstructorError function in tablib

def find_python_name(self, name, mark):
        if not name:
            raise ConstructorError("while constructing a Python object", mark,
                                   "expected non-empty name appended to the tag", mark)
        if u'.' in name:
            # Python 2.4 only
            # module_name, object_name = name.rsplit('.', 1)
            items = name.split('.')
            object_name = items.pop()
            module_name = '.'.join(items)
        else:
            module_name = '__builtin__'
            object_name = name
        try:
            __import__(module_name)
        except ImportError, exc:
            raise ConstructorError("while constructing a Python object", mark,
                                   "cannot find module %r (%s)" % (module_name.encode('utf-8'), exc), mark)
        module = sys.modules[module_name]

if not name:
            raise ConstructorError("while constructing a Python object", mark,
                                   "expected non-empty name appended to the tag", mark)
        if u'.' in name:
            # Python 2.4 only
            # module_name, object_name = name.rsplit('.', 1)
            items = name.split('.')
            object_name = items.pop()
            module_name = '.'.join(items)
        else:
            module_name = '__builtin__'
            object_name = name
        try:
            __import__(module_name)
        except ImportError, exc:
            raise ConstructorError("while constructing a Python object", mark,
                                   "cannot find module %r (%s)" % (module_name.encode('utf-8'), exc), mark)
        module = sys.modules[module_name]
        if not hasattr(module, object_name):
            raise ConstructorError("while constructing a Python object", mark,
                                   "cannot find %r in the module %r" % (object_name.encode('utf-8'),
                                                                        module.__name__), mark)
        return getattr(module, object_name)

# Python 2.4 only
            # module_name, object_name = name.rsplit('.', 1)
            items = name.split('.')
            object_name = items.pop()
            module_name = '.'.join(items)
        else:
            module_name = '__builtin__'
            object_name = name
        try:
            __import__(module_name)
        except ImportError, exc:
            raise ConstructorError("while constructing a Python object", mark,
                                   "cannot find module %r (%s)" % (module_name.encode('utf-8'), exc), mark)
        module = sys.modules[module_name]
        if not hasattr(module, object_name):
            raise ConstructorError("while constructing a Python object", mark,
                                   "cannot find %r in the module %r" % (object_name.encode('utf-8'),
                                                                        module.__name__), mark)
        return getattr(module, object_name)

def find_python_module(self, name, mark):
        if not name:
            raise ConstructorError("while constructing a Python module", mark,
                                   "expected non-empty name appended to the tag", mark)
        try:
            __import__(name)
        except ImportError, exc:
            raise ConstructorError("while constructing a Python module", mark,
                                   "cannot find module %r (%s)" % (name.encode('utf-8'), exc), mark)
        return sys.modules[name]

def construct_mapping(self, node, deep=False):
        if not isinstance(node, MappingNode):
            raise ConstructorError(None, None,
                                   "expected a mapping node, but found %s" % node.id,
                                   node.start_mark)
        mapping = {}
        for key_node, value_node in node.value:
            key = self.construct_object(key_node, deep=deep)
            try:
                hash(key)
            except TypeError, exc:
                raise ConstructorError("while constructing a mapping", node.start_mark,
                                       "found unacceptable key (%s)" % exc, key_node.start_mark)
            value = self.construct_object(value_node, deep=deep)
            mapping[key] = value
        return mapping

merge.extend(value_node.value)
                elif isinstance(value_node, SequenceNode):
                    submerge = []
                    for subnode in value_node.value:
                        if not isinstance(subnode, MappingNode):
                            raise ConstructorError("while constructing a mapping",
                                                   node.start_mark,
                                                   "expected a mapping for merging, but found %s"
                                                   % subnode.id, subnode.start_mark)
                        self.flatten_mapping(subnode)
                        submerge.append(subnode.value)
                    submerge.reverse()
                    for value in submerge:
                        merge.extend(value)
                else:
                    raise ConstructorError("while constructing a mapping", node.start_mark,
                                           "expected a mapping or list of mappings for merging, but found %s"
                                           % value_node.id, value_node.start_mark)
            elif key_node.tag == u'tag:yaml.org,2002:value':
                key_node.tag = u'tag:yaml.org,2002:str'
                index += 1
            else:
                index += 1
        if merge:
            node.value = merge + node.value

def construct_object(self, node, deep=False):
        if deep:
            old_deep = self.deep_construct
            self.deep_construct = True
        if node in self.constructed_objects:
            return self.constructed_objects[node]
        if node in self.recursive_objects:
            raise ConstructorError(None, None,
                                   "found unconstructable recursive node", node.start_mark)
        self.recursive_objects[node] = None
        constructor = None
        tag_suffix = None
        if node.tag in self.yaml_constructors:
            constructor = self.yaml_constructors[node.tag]
        else:
            for tag_prefix in self.yaml_multi_constructors:
                if node.tag.startswith(tag_prefix):
                    tag_suffix = node.tag[len(tag_prefix):]
                    constructor = self.yaml_multi_constructors[tag_prefix]
                    break
            else:
                if None in self.yaml_multi_constructors:
                    tag_suffix = node.tag
                    constructor = self.yaml_multi_constructors[None]

def construct_yaml_pairs(self, node):
        # Note: the same code as `construct_yaml_omap`.
        pairs = []
        yield pairs
        if not isinstance(node, SequenceNode):
            raise ConstructorError("while constructing pairs", node.start_mark,
                                   "expected a sequence, but found %s" % node.id, node.start_mark)
        for subnode in node.value:
            if not isinstance(subnode, MappingNode):
                raise ConstructorError("while constructing pairs", node.start_mark,
                                       "expected a mapping of length 1, but found %s" % subnode.id,
                                       subnode.start_mark)
            if len(subnode.value) != 1:
                raise ConstructorError("while constructing pairs", node.start_mark,
                                       "expected a single mapping item, but found %d items" % len(subnode.value),
                                       subnode.start_mark)
            key_node, value_node = subnode.value[0]
            key = self.construct_object(key_node)
            value = self.construct_object(value_node)
            pairs.append((key, value))

def construct_yaml_binary(self, node):
        value = self.construct_scalar(node)
        try:
            return str(value).decode('base64')
        except (binascii.Error, UnicodeEncodeError), exc:
            raise ConstructorError(None, None,
                                   "failed to decode base64 data: %s" % exc, node.start_mark)