code: func (b *backendInstance) PTCIncreaseApproval(opts *bind.TransactOpts,
  	spender common.Address, addedVal *big.Int) (*types.Transaction, error) {
  	ctx2, cancel := b.addTimeout(opts.Context)
  	defer cancel()
  
  	opts.Context = ctx2
  
  	tx, err := b.ptc.IncreaseApproval(opts, spender, addedVal)
  	if err != nil {
  		return nil, fmt.Errorf("failed to PTC increase approval: %s", err)
  	}
  	return tx, nil
  }
docs: // PTCIncreaseApproval calls increaseApproval method of Privatix token contract.