What was the change in cash flow from operating activities from 2018 to 2019?
{"Cash flows provided by (used in) -- Operating activities": {"2019": 35746, "2018": 34339}, "Cash flows provided by (used in) -- Investing activities": {"2019": -17581, "2018": -17934}, "Cash flows provided by (used in) -- Financing activities": {"2019": -18164, "2018": -15377}, "Cash flows provided by (used in) -- Increase in cash, cash equivalents and restricted cash": {"2019": 1, "2018": 1028}}
cash_flow_2019 = df["Cash flows provided by (used in) -- Operating activities"]["2019"]
cash_flow_2018 = df["Cash flows provided by (used in) -- Operating activities"]["2018"]
answer = cash_flow_2019 - cash_flow_2018