How to use the snakeviz.pstatsloader.BaseStat function in snakeviz

if parent:
                self.parents.append( parent )
                parent.children.append( self )
    def child_cumulative_time( self, child ):
        total = self.cummulative
        if total:
            try:
                (cc,nc,tt,ct) = child.callers[ self.key ]
            except TypeError as err:
                ct = child.callers[ self.key ]
            return float(ct)/total
        return 0



class PStatGroup( BaseStat ):
    """A node/record that holds a group of children but isn't a raw-record based group"""
    # if LOCAL_ONLY then only take the raw-record's local values, not cummulative values
    LOCAL_ONLY = False
    def __init__( self, directory='', filename='', name='', children=None, local_children=None, tree=TREE_CALLS ):
        self.directory = directory
        self.filename = filename
        self.name = ''
        self.key = (directory,filename,name)
        self.children = children or []
        self.parents = []
        self.local_children = local_children or []
        self.tree = tree
    def __repr__( self ):
        return '%s( %r,%r,%s )'%(self.__class__.__name__,self.directory, self.filename, self.name)
    def finalize( self, already_done=None ):
        """Finalize our values (recursively) taken from our children"""

def recursive_distinct( self, already_done=None, attribute='children' ):
        if already_done is None:
            already_done = {}
        for child in getattr(self,attribute,()):
            if child not in already_done:
                already_done[child] = True
                yield child
                for descendent in child.recursive_distinct( already_done=already_done, attribute=attribute ):
                    yield descendent

    def descendants( self ):
        return list( self.recursive_distinct( attribute='children' ))
    def ancestors( self ):
        return list( self.recursive_distinct( attribute='parents' ))

class PStatRow( BaseStat ):
    """Simulates a HotShot profiler record using PStats module"""
    def __init__( self, key, raw ):
        self.children = []
        self.parents = []
        file,line,func = self.key = key
        try:
            dirname,basename = os.path.dirname(file),os.path.basename(file)
        except ValueError as err:
            dirname = ''
            basename = file
        nc, cc, tt, ct, callers = raw
        if nc == cc == tt == ct == 0:
            raise ValueError( 'Null stats row' )
        (
            self.calls, self.recursive, self.local, self.localPer,
            self.cummulative, self.cummulativePer, self.directory,