code: func (c *EnvConfig) Copy() *EnvConfig {
  	if c == nil {
  		return nil
  	}
  
  	var o EnvConfig
  
  	if c.Blacklist != nil {
  		o.Blacklist = append([]string{}, c.Blacklist...)
  	}
  
  	if c.Custom != nil {
  		o.Custom = append([]string{}, c.Custom...)
  	}
  
  	o.Pristine = c.Pristine
  
  	if c.Whitelist != nil {
  		o.Whitelist = append([]string{}, c.Whitelist...)
  	}
  
  	return &o
  }
docs: // Copy returns a deep copy of this configuration.