Example: an MX investment transaction with
account.balance: 5200.10, account.guid: "ACT-123", amount: 925.25, currency_code: "USD", description: "BUY AAPL", transacted_at: "2024-01-15", posted_at: "2024-01-15", category: "buy" maps to Meld cashBalance: 5200.10, accountId: "ACT-123", amount: 925.25, currency: "USD", description: "BUY AAPL", transactionDate: "2024-01-15", postedDate: "2024-01-15", type: "buy".