Call Matlab Function with .mat file content as argument from Python

I am building a software and a part of this software needs to read a .mat file and give the content to a matlab function as argument. The problem is that I have bad data structure I guess.

In fact my Matlab structure called handles doesn't have the same data structure than my handles in my Python (after conversion)

When I load the .mat file from python with scipy.io.loadmat(), I have those 4 keys:

So in handles.simulation there supposed to be this content:

So I use matlab.engine to call matlab function in my case the function is called VS_Parametrise and when I pass my handles which is a dict:

# -*- coding: utf-8 -*-

import sys
import os
import Tkinter
import numpy as np

from tkFileDialog import askopenfilename
from structDataConfFile import structConfFile

try:
    import matlab.engine
except:
    print "No matlabEngine installed"
    print "Running installation procedure..."
    print " "
    import installMatlabEngine
    print " "
    print "Application will exit now..."
    print "Please re-run this program to continue installation!"
    print " "
    exit()

# Environment PATH
Mlab = os.environ.get("MATLAB")
vssFolderPath=os.environ.get("CONTIAME")+'/4_Tools/Veh_Sim_Suite/VSimu'
ContimodelPath=os.environ.get("CONTIAME")

FILETYPES = [ ("text files", "*.mat") ]

handles = dict()

def selectConfFile():
    """ Return the path of .mat file

    Function that open files browser to choose a .mat file and build handles
    dictionary.
    """
    Tkinter.Tk().withdraw() # Close the root window
    in_path = askopenfilename(filetypes=FILETYPES)
    if len(in_path) == 0:
        handles['Simulation'] = list()
    elif len(in_path) > 0:
        handles['Simulation'] = structConfFile(in_path) # HERE I FILL SIMULATION
    handles['contimodel_path'] = ContimodelPath
    return in_path

def Parametrize(confFile):
    """ Return

    Argument:
    confFile    --  str()   Configuration File path

    Function that call MatLab function passing handles structure/dict as
    argument. The return value of MatLab function called VS_Parametrize(handles)
    is the modified handles structure.
    """
    eng = matlab.engine.start_matlab()
    eng.addpath(vssFolderPath)
    eng.VS_Parametrise(handles) ############# HERE I CALL VS_PARAMETRIZE

In my matlab function handles.simulation there are structure of structure of structure.

In Python it should be dictionary of dictionary of dictionary but I get this error:

And I don't understand why when i load the file in Python the first floor of the data structure is a dict and the second is a numpy.ndarray (1st floor: simulation, 2nd floor: parameter/info). Here is more documentation about Matlab to Python variable

Any idea ?