/// Named constant for `amount`.
pub const ARG_AMOUNT: &str = "amount";

/// Named constant for method `pay`.
pub const METHOD_PAY: &str = "pay";

/// Storage for standard payment contract hash.
pub const HASH_KEY: &str = "standard_payment_hash";
/// Storage for standard payment access key.
pub const ACCESS_KEY: &str = "standard_payment_access";
