code: func (c *Container) MergeEnvironmentVariables(envVars map[string]string) {
  	c.lock.Lock()
  	defer c.lock.Unlock()
  
  	// don't assume that the environment variable map has been initialized by others
  	if c.Environment == nil {
  		c.Environment = make(map[string]string)
  	}
  	for k, v := range envVars {
  		c.Environment[k] = v
  	}
  }
docs: // MergeEnvironmentVariables appends additional envVarName:envVarValue pairs to
  // the the container's enviornment values structure