Enabling the reading of N and M value from the json request

For this commit only the first element from the {N, M} list is read
and assigned.

This is better than not reading this value at all.

the commit also updates test_files and test data files with correct
values for the effective_freq_slot attribute

Signed-off-by: EstherLerouzic <esther.lerouzic@orange.com>
Change-Id: I1e60fe833ca1092b40de27c8cbfb13083810414e

gnpy/tools/cli_examples.py

@@ -187,6 +187,7 @@ def transmission_main_example(args=None):
     params['loose_list'] = ['strict']
     params['format'] = ''
     params['path_bandwidth'] = 0
+    params['effective_freq_slot'] = None
     trx_params = trx_mode_params(equipment)
     if args.power:
         trx_params['power'] = db2lin(float(args.power)) * 1e-3