code: def find_lib_directory(self):
          
          lib_directory = None
          if self.lib_micro_version in self.lib_directories:
              lib_directory = self.lib_micro_version
          elif self.lib_minor_version in self.lib_directories:
              lib_directory = self.lib_minor_version
          elif self.lib_major_version in self.lib_directories:
              lib_directory = self.lib_major_version
          else:
              for lv in [self.lib_micro_version, self.lib_minor_version, self.lib_major_version]:
                  for d in self.lib_directories:
                      if lv in d:
                          lib_directory = d
                          break
                  else:
                      continue
                  break
          return lib_directory
docs: Find the optimal lib directory.