Function parse_hmac_list 

pub fn parse_hmac_list(
    py: Python<'_>,
    hmac_list: &PyObject,
) -> PyResult<HashMap<String, String>>

Convert a Python list of {"access_key": …, "secret_key": …} dicts into a Rust HashMap<access_key, secret_key>.

Errors

Returns a [pyo3::PyErr] if hmac_list cannot be extracted as Vec<HashMap<String, String>> or if any entry is missing access_key or secret_key.