def session_hist_tex(f, session_data, threshold_requests_per_session):
    """
    Write session caracteristics in latex file
    
    Parameters
    ----------
        f: file
        
        session_data: pandas dataframe of sessions
                                
        threshold_requests_per_session: int for filter number of requests per session
        
    Returns
    -------
        File (Optionnal)
    """
    digit_dic = {'0': 'Zero', '1': 'One', '2': 'Two', '3': 'Three', '4':
        'Four', '5': 'Five', '6': 'Six', '7': 'Seven', '8': 'Eight', '9':
        'Nine'}
    f.write('\n% 2. Histogram sessions with given requests')
    f.write('\n\\newcommand{\\%s}{%d}' % ('ThresholdRequestsPerSession',
        threshold_requests_per_session))
    for reqs in range(1, threshold_requests_per_session + 1):
        num_of_sessions = session_data[session_data.requests == reqs].shape[0]
        pc_of_sessions = 100.0 * num_of_sessions / session_data.shape[0]
        f.write('\n\\newcommand{\\%s}{%d}' % ('SessionsWith%sRequests' %
            digit_dic[str(reqs)], num_of_sessions))
        f.write('\n\\newcommand{\\%s}{%.1f}' % ('PCSessionsWith%sRequests' %
            digit_dic[str(reqs)], pc_of_sessions))
    num_of_sessions = session_data[session_data.requests >
        threshold_requests_per_session].shape[0]
    pc_of_sessions = 100.0 * num_of_sessions / session_data.shape[0]
    f.write('\n\\newcommand{\\%s}{%d}' % ('SessionsWithMT%sRequests' %
        digit_dic[str(threshold_requests_per_session)], num_of_sessions))
    f.write('\n\\newcommand{\\%s}{%.1f}' % ('PCSessionsWithMT%sRequests' %
        digit_dic[str(threshold_requests_per_session)], pc_of_sessions))
    return f
