Actions firmware appears to be bundled with a script which dictates how the firmware is to be transferred to the device. So the Actions firmware tool actually provides an interface in python on communicating with the hardware.

It's worth noting that the interface provides "DownloadImage" and "DownloadMem" indicating a host to device firmware and memory transfer, and "UploadMem" indicating a device to host memory transfer.
In fact, DownloadMem maps directly to ADFUWrite, and UploadMem maps directly to ADFURead.

Here's the full provided interface:

int __cdecl Py_CallEntry(U32 uId, U32 uAddress)
int __cdecl Py_CloseDevice(U32 uId)
int __cdecl Py_DetachDevice(U32 uId)
int __cdecl Py_DoUserComm(U32 uId, unsigned __int8 *USBC, unsigned __int8 *buffer)
int __cdecl Py_DownloadImage(U32 uId, U32 uType, U32 uSubType, U32 uPageSize, U32 uDiskCap, U32 uAddr, int nStartPer, int nEndPer)
int __cdecl Py_DownloadMem(U32 uId, int nType, U32 uAddress, unsigned __int8 *buffer, U32 uLength)
int __cdecl Py_EjectDevice(U32 uId)
const char *__cdecl Py_ExtractScript(const char *szFirmware)
int __cdecl Py_GetConfigFile(char *szType, int nSubType, unsigned __int8 *buffer, int nOffset, int nLength)
int __cdecl Py_GetFileInImage(const char *szImage, const char *szFile, unsigned __int8 *buffer)
U32 __cdecl Py_GetFirmwareBin(unsigned __int8 *fwBin, char *tmpImg)
const char *__cdecl Py_GetFirmwareCfg(const char *szFirmware, const char *szKey)
int __cdecl Py_GetImageSize(U32 uId, U32 uType, U32 uSubType, U32 uPageSize, U32 uDiskCap)
int __cdecl Py_GetProductionConfig(const char *szType, U32 nSubType, unsigned __int8 *szCfgValue)
int __cdecl Py_GetStatus(U32 uId, unsigned __int8 *buffer)
int __cdecl Py_OpenDevice(U32 uId)
int __cdecl Py_OpenFirmware(const char *szFirmwareFile, unsigned __int8 *fwBin, char *szImageFile)
int __cdecl Py_PollReady(U32 uId)
int __cdecl Py_PyThreadExit(U32 uId, int nExitCode)
int __cdecl Py_ReOpenDevice(U32 uId, int nType, int uTimeout)
int __cdecl Py_ReadFileInFW(const char *szImage, const char *szFileName, U32 uOffset, U32 uToRead, unsigned __int8 *buffer, U32 uAlign)
int __cdecl Py_Recv(U32 uId, unsigned __int8 *usbc, unsigned __int8 *buffer, U32 uLength)
int __cdecl Py_Send(U32 uId, unsigned __int8 *usbc, unsigned __int8 *buffer, U32 uLength)
int __cdecl Py_SetCommTimeout(U32 uId, U32 uMS)
void __cdecl Py_SetLibPath(const char *path)
int __cdecl Py_SetProductionConfig(const char *szType, U32 nSubType, unsigned __int8 *szCfgValue)
int __cdecl Py_ShowMessage(int nType, U32 nSubType, const unsigned __int8 *buffer, int nLength)
int __cdecl Py_SwitchFW(U32 uId, U32 uAddress)
int __cdecl Py_SwitchToAdfu(U32 uId, int uTimeout)
int __cdecl Py_UpdateCapacity(U32 uId, U32 uCapacity)
int __cdecl Py_UpdateProgress(U32 uId, int nPercent)
int __cdecl Py_UpdateStatus(U32 uId, const char *buffer)
int __cdecl Py_UploadMem(U32 uId, int nType, U32 uAddress, unsigned __int8 *buffer, U32 uLength)