code: def find_projects(self, file_identifier=".project"):
          
          projects = []
          for d in self.subdirs():
              project_file = os.path.join(self.directory, d, file_identifier)
              if os.path.isfile(project_file):
                  projects.append(d)
          return projects
docs: Search all directory recursively for subdirs
          with `file_identifier' in it.
  
          :type file_identifier: str
          :param file_identifier: File identier, .project by default.
  
          :rtype: list
          :return: The list of subdirs with a `file_identifier' in it.