code: def set_config_token_from_env(section, token, config):
      '''Given a config section and token, checks for an appropriate
      environment variable. If the variable exists, sets the config entry to
      its value.
  
      The environment variable checked is of the form SECTION_TOKEN, all
      upper case, with any dots replaced by underscores.
  
      Returns True if the environment variable exists and was used, or
      False otherwise.
  
      '''
      env_var_name = ''.join([section.upper(), '_',
                              token.upper().replace('.', '_')])
      env_var = os.environ.get(env_var_name)
      if env_var is None:
          return False
      config.set(section, token, env_var)
      return Truf set_config_token_from_env(section, token, config):
      '''Given a config section and token, checks for an appropriate
      environment variable. If the variable exists, sets the config entry to
      its value.
  
      The environment variable checked is of the form SECTION_TOKEN, all
      upper case, with any dots replaced by underscores.
  
      Returns True if the environment variable exists and was used, or
      False otherwise.
  
      '''
      env_var_name = ''.join([section.upper(), '_',
                              token.upper().replace('.', '_')])
      env_var = os.environ.get(env_var_name)
      if env_var is None:
          return False
      config.set(section, token, env_var)
      return True
docs: Given a config section and token, checks for an appropriate
      environment variable. If the variable exists, sets the config entry to
      its value.
  
      The environment variable checked is of the form SECTION_TOKEN, all
      upper case, with any dots replaced by underscores.
  
      Returns True if the environment variable exists and was used, or
      False otherwise.