build/change_trust.go
func Trust(code, issuer string, args ...interface{}) (result ChangeTrustBuilder) {
	mutators := []interface{}{
		CreditAsset(code, issuer),
	}

	limitSet := false

	for _, mut := range args {
		mutators = append(mutators, mut)
		_, isLimit := mut.(Limit)
		if isLimit {
			limitSet = true
		}
	}

	if !limitSet {
		mutators = append(mutators, MaxLimit)
	}

	return ChangeTrust(mutators...)
}
func Trust(code, issuer string, args ...interface{}) (result ChangeTrustBuilder) {
	mutators := []interface{}{
		CreditAsset(code, issuer),
	}

	limitSet := false

	for _, mut := range args {
		mutators = append(mutators, mut)
		_, isLimit := mut.(Limit)
		if isLimit {
			limitSet = true
		}
	}

	if !limitSet {
		mutators = append(mutators, MaxLimit)
	}

	return ChangeTrust(mutators...)
}
// Trust is a helper that creates ChangeTrustBuilder