Calling User specified PROTOCOL from Python

Suppose:
There is PORTOCOL which is not defined in UEFI/PI and is built in BIOS image.
This PROTOCOL interface is known by C language header file:

#ifndef _XYZ_DXE_H_
#define _XYZ_DXE_H_

#define USER_XYZ_PROTOCOL_GIUD \
  { \
    0x2a339172, 0x7ef6, 0x4f2b, { 0x95, 0xb9, 0x83, 0xf2, 0x15, 0x18, 0xeb, 0xf7} \
  }


typedef struct _USER_XYZ_PROTOCOL USER_XYZ_PROTOCOL;

typedef
EFI_STATUS
(EFIAPI *USER_XYZ_GET_VERSION)(
  IN  CONST USER_XYZ_PROTOCOL     *This,
  OUT UINT64                      *VersionSize
  );

typedef
EFI_STATUS
(EFIAPI *USER_XYZ_DUMMY)(
  VOID
  );

///
/// XYZ Protocol structure
///
struct _USER_XYZ_PROTOCOL {
  USER_XYZ_GET_VERSION    GetVersion;
  USER_XYZ_DUMMY          Dummy;
};

#endif // _XYZ_DXE_H_

PROTOCOL's EfiPy form and How to use it:
#
# xyzProtocol.py
#

#
# XYX PROTOCOL declare in EfiPy format
#
from EfiPy import *

#
# XYZ protocol GUID
#
# #define USER_XYZ_PROTOCOL_GIUD \
#   { \
#     0x2a339172, 0x7ef6, 0x4f2b, { 0x95, 0xb9, 0x83, 0xf2, 0x15, 0x18, 0xeb, 0xf7} \
#   }
# EFI_GUID gUserXyzProtocolGuid = USER_XYZ_PROTOCOL_GIUD;
#
gUserXyzProtocolGuid                 = \
  EFI_GUID (0x2a339172, 0x7ef6, 0x4f2b, (0x95, 0xb9, 0x83, 0xf2, 0x15, 0x18, 0xeb, 0xf7))

#
# XYZ protocol declare
#
# typedef struct _USER_XYZ_PROTOCOL USER_XYZ_PROTOCOL;
#
class USER_XYZ_PROTOCOL (Structure):
  pass

#
# USER_XYZ_GET_VERSION function declare
#
# typedef
# EFI_STATUS
# (EFIAPI *USER_XYZ_GET_VERSION)(
#   IN  CONST USER_XYZ_PROTOCOL     *This,
#   OUT UINT64                      *VersionSize
#   );
#
USER_XYZ_GET_VERSION = CFUNCTYPE (
  EFI_STATUS,
  POINTER (USER_XYZ_PROTOCOL),
  POINTER (UINT64)
  )

#
# USER_XYZ_DUMMY function declare
#
# typedef
# EFI_STATUS
#   (EFIAPI *USER_XYZ_DUMMY)(
#   VOID
#   );
#
# Return type: EFI_STATUS
# Input parameter: None
#
USER_XYZ_DUMMY = CFUNCTYPE (
  EFI_STATUS
  )

#
# XYZ Protocol structure
#
# struct _USER_XYZ_PROTOCOL {
#   USER_XYZ_GET_VERSION    GetVersion;
#   USER_XYZ_DUMMY          Dummy;
# };
#
USER_XYZ_PROTOCOL._fields_ = [
  ("GetVersion",  USER_XYZ_GET_VERSION),
  ("Dummy",       USER_XYZ_DUMMY)
  ]


#
# Test program for verifying protocol conversation
#
if __name__ == '__main__':

  Interface = PVOID ()
  Status = gBS.LocateProtocol (
                 byref (gUserXyzProtocolGuid),
                 None,
                 byref (Interface)
                 )

  if Status != 0x00:
    print "Locate Protocol Error (Status:%x)" % Status
    exit (0)

  XyzProtocol = cast (Interface, POINTER(USER_XYZ_PROTOCOL))

  Version = UINT64(0)

  Status = XyzProtocol[0].GetVersion (XyzProtocol, byref(Version))

  print "Get Version: %x (Status:%x)" % (Version.value, Status)

Advanced
After this EfiPy protocol program test is done, it can be put into package folder, including __init__.py.

Setting PYTHONPATH uefi shell environment variable lets user specified protocol in anywhere.

Example: Folder fs0:\Xyz includes xyzProtocol.py and __init__.py 

set PYTHONPATH fs0:\Xyz

USER_XYZ_PROTOCOL can be called from anywhere by

import xyzProtocol

Q&A: Should EfiPy programmer needs to reference protocol implementation source code?
Answer: 
No, it is the same as EFI caller program, EfiPy programmer needs Protocol header file and transfer it to Python code, only.

Q&A: Should python.efi needs to be compiled, again, for user specified PROTOCOL?
Answer:
No, python.efi includes ctypes.
ctypes for UEFI is a foreign function library for Python. It provides C compatible data types, and allows calling functions in UEFI PROTOCOL. It can be used to wrap PROTOCOLs in pure Python. (ref. from Here)