How to use the b2.manager.get_manager function in b2

def create_typed_metatarget(name, type, sources, requirements, default_build, usage_requirements):
    
    from b2.manager import get_manager
    t = get_manager().targets()
    
    project = get_manager().projects().current()
        
    return t.main_target_alternative(
        TypedTarget(name, project, type,
                    t.main_target_sources(sources, name),
                    t.main_target_requirements(requirements, project),
                    t.main_target_default_build(default_build, project),
                    t.main_target_usage_requirements(usage_requirements, project)))

def start_building (self, main_target_instance):
        """ Helper rules to detect cycles in main target references.
        """
        if self.targets_being_built_.has_key(id(main_target_instance)):
            names = []
            for t in self.targets_being_built_.values() + [main_target_instance]:
                names.append (t.full_name())
            
            get_manager().errors()("Recursion in main target references\n")
        
        self.targets_being_built_[id(main_target_instance)] = main_target_instance

def symlink(targets, sources):

    from b2.manager import get_manager
    t = get_manager().targets()
    p = get_manager().projects().current()

    return t.main_target_alternative(
        SymlinkTarget(p, targets,
                      # Note: inline targets are not supported for symlink, intentionally,
                      # since it's used to linking existing non-local targets.
                      sources))

def option(self, name, value):
        assert is_iterable(name) and isinstance(name[0], basestring)
        assert is_iterable(value) and isinstance(value[0], basestring)
        name = name[0]
        if not name in ["site-config", "user-config", "project-config"]:
            get_manager().errors()("The 'option' rule may be used only in site-config or user-config")

        option.set(name, value[0])

def start_building (self, main_target_instance):
        """ Helper rules to detect cycles in main target references.
        """
        if self.targets_being_built_.has_key(id(main_target_instance)):
            names = []
            for t in self.targets_being_built_.values() + [main_target_instance]:
                names.append (t.full_name())
            
            get_manager().errors()("Recursion in main target references\n")
        
        self.targets_being_built_[id(main_target_instance)] = main_target_instance

def translate_indirect(properties, context_module):
    """Assumes that all feature values that start with '@' are
    names of rules, used in 'context-module'. Such rules can be
    either local to the module or global. Qualified local rules
    with the name of the module."""
    result = []
    for p in properties:
        if p.value()[0] == '@':
            q = qualify_jam_action(p.value()[1:], context_module)
            get_manager().engine().register_bjam_action(q)
            result.append(Property(p.feature(), '@' + q, p.condition()))
        else:
            result.append(p)

    return result

def manifest(targets,sources=None,properties=None):
    if 'on' in properties.get(''):
        get_manager().engine().set_update_action('msvc.manifest', targets, sources, properties)

def start_building (self, main_target_instance):
        """ Helper rules to detect cycles in main target references.
        """
        assert isinstance(main_target_instance, MainTarget)
        if id(main_target_instance) in self.targets_being_built_:
            names = []
            for t in self.targets_being_built_.values() + [main_target_instance]:
                names.append (t.full_name())

            get_manager().errors()("Recursion in main target references\n")

        self.targets_being_built_[id(main_target_instance)] = main_target_instance

# The simple case if when a name
        # of source has single dot. Then, we take the part before
        # dot. Several dots can be caused by:
        # - Using source file like a.host.cpp
        # - A type which suffix has a dot. Say, we can
        #   type 'host_cpp' with extension 'host.cpp'.
        # In the first case, we want to take the part till the last
        # dot. In the second case -- no sure, but for now take
        # the part till the last dot too.
        name = os.path.splitext(sources[0].name())[0]
                        
        for s in sources[1:]:
            n2 = os.path.splitext(s.name())
            if n2 != name:
                get_manager().errors()(
                    "%s: source targets have different names: cannot determine target name"
                    % (self.id_))
                        
        # Names of sources might include directory. We should strip it.
        return self.determine_target_name(sources[0].name())

def start_building (self, main_target_instance):
        """ Helper rules to detect cycles in main target references.
        """
        assert isinstance(main_target_instance, MainTarget)
        if id(main_target_instance) in self.targets_being_built_:
            names = []
            for t in self.targets_being_built_.values() + [main_target_instance]:
                names.append (t.full_name())

            get_manager().errors()("Recursion in main target references\n")

        self.targets_being_built_[id(main_target_instance)] = main_target_instance