code: def verify_dir_structure(full_path):
      '''Check if given directory to see if it is usable by s2.
  
      Checks that all required directories exist under the given 
      directory, and also checks that they are writable.
  
      '''
      if full_path == None:
          return False
      r = True
      for d2c in PREDEFINED_DIR_NAMES:
          #if d2c == "s2":
          #    d2c = ".s2"
          cp2c = os.path.join(full_path, d2c)  #complete path to check
          if not os.path.isdir(cp2c):
              r = False
              break
          else:  #exists, let's check it's writable
              if not os.access(cp2c, os.W_OK): 
                  r = False
                  break
      return f verify_dir_structure(full_path):
      '''Check if given directory to see if it is usable by s2.
  
      Checks that all required directories exist under the given 
      directory, and also checks that they are writable.
  
      '''
      if full_path == None:
          return False
      r = True
      for d2c in PREDEFINED_DIR_NAMES:
          #if d2c == "s2":
          #    d2c = ".s2"
          cp2c = os.path.join(full_path, d2c)  #complete path to check
          if not os.path.isdir(cp2c):
              r = False
              break
          else:  #exists, let's check it's writable
              if not os.access(cp2c, os.W_OK): 
                  r = False
                  break
      return r
docs: Check if given directory to see if it is usable by s2.
  
      Checks that all required directories exist under the given 
      directory, and also checks that they are writable.