def mkdir(self, astr_dirSpec):
            """
            Given an <astr_dirSpec> in form '/a/b/c/d/.../f',
            create that path in the internal stree, creating all
            intermediate nodes as necessary

            :param astr_dirSpec:
            :return:
            """
            if astr_dirSpec != '/' and astr_dirSpec != "//":
                str_currentPath = self.cwd()
                l_pathSpec = astr_dirSpec.split('/')
                if not len(l_pathSpec[0]):
                    self.cd('/')
                    l_nodesDepth = l_pathSpec[1:]
                else:
                    l_nodesDepth = l_pathSpec
                for d in l_nodesDepth:
                    self.mkcd(d)
                self.cd(str_currentPath)