How to use PyYAML - 10 common examples

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 '.' in name:
            module_name, object_name = name.rsplit('.', 1)
        else:
            module_name = 'builtins'
            object_name = name
        try:
            __import__(module_name)
        except ImportError as exc:
            raise ConstructorError("while constructing a Python object", mark,
                    "cannot find module %r (%s)" % (module_name, 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, module.__name__), mark)

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 '.' in name:
            module_name, object_name = name.rsplit('.', 1)
        else:
            module_name = 'builtins'
            object_name = name
        try:
            __import__(module_name)
        except ImportError as exc:
            raise ConstructorError("while constructing a Python object", mark,
                    "cannot find module %r (%s)" % (module_name, 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, module.__name__), mark)
        return getattr(module, object_name)

def open(self):
        if self.closed is None:
            self.emit(StreamStartEvent(encoding=self.use_encoding))
            self.closed = False
        elif self.closed:
            raise SerializerError("serializer is closed")
        else:
            raise SerializerError("serializer is already opened")

def close(self):
        if self.closed is None:
            raise SerializerError("serializer is not opened")
        elif not self.closed:
            self.emit(StreamEndEvent())
            self.closed = True

def serialize(self, node):
        if self.closed is None:
            raise SerializerError("serializer is not opened")
        elif self.closed:
            raise SerializerError("serializer is closed")
        self.emit(DocumentStartEvent(explicit=self.use_explicit_start,
            version=self.use_version, tags=self.use_tags))
        self.anchor_node(node)
        self.serialize_node(node, None, None)
        self.emit(DocumentEndEvent(explicit=self.use_explicit_end))
        self.serialized_nodes = {}
        self.anchors = {}
        self.last_anchor_id = 0

def open(self):
        if self.closed is None:
            self.emit(StreamStartEvent(encoding=self.use_encoding))
            self.closed = False
        elif self.closed:
            raise SerializerError("serializer is closed")
        else:
            raise SerializerError("serializer is already opened")

def serialize(self, node):
        if self.closed is None:
            raise SerializerError("serializer is not opened")
        elif self.closed:
            raise SerializerError("serializer is closed")
        self.emit(DocumentStartEvent(explicit=self.use_explicit_start,
            version=self.use_version, tags=self.use_tags))
        self.anchor_node(node)
        self.serialize_node(node, None, None)
        self.emit(DocumentEndEvent(explicit=self.use_explicit_end))
        self.serialized_nodes = {}
        self.anchors = {}
        self.last_anchor_id = 0

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)
            if not isinstance(key, collections.Hashable):
                raise ConstructorError("while constructing a mapping", node.start_mark,
                        "found unhashable key", key_node.start_mark)
            value = self.construct_object(value_node, deep=deep)
            mapping[key] = value
        return mapping

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)
            if not isinstance(key, collections.Hashable):
                raise ConstructorError("while constructing a mapping", node.start_mark,
                        "found unhashable key", key_node.start_mark)
            value = self.construct_object(value_node, deep=deep)
            mapping[key] = value
        return mapping

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 as exc:
            raise ConstructorError("while constructing a Python module", mark,
                    "cannot find module %r (%s)" % (name, exc), mark)
        return sys.modules[name]