B2OC: add a wrapper to check process argument

• Add a python wrapper to check the process argument is either hlt2 or spruce.
• Raise ConfigurationError instead of AssertionError.
• Apply the wrapper to some line builders in bbaryon_to_cbaryon_hh

To-do:

• Apply the wrapper to all line builder with assert inside. This should be done after !1035 (merged) is merged to avoid conflict.
• Remove all @configurable in line builders

Related to #282 (closed).

cc @abertoli

Hlt/Hlt2Conf/python/Hlt2Conf/lines/b_to_open_charm/b_to_cbaryon_hh.py

@@ -13,7 +13,7 @@
 """
 from __future__ import absolute_import, division, print_function
 
-from PyConf import configurable
+from Hlt2Conf.lines.b_to_open_charm.utils import check_process
 
 from Hlt2Conf.lines.b_to_open_charm.builders import basic_builder
 from Hlt2Conf.lines.b_to_open_charm.builders import cbaryon_builder
@@ -23,11 +23,8 @@ from Hlt2Conf.lines.b_to_open_charm.builders import b_builder
 ###########################################################
 # Form the B+ -> Lcbar- p+ pi+, Lcbar- --> pbar K+ pi-
 ##########################################################
-@configurable
+@check_process
 def make_BuToLcmPPi_LcmToPKPi(process):
-    assert process in ['hlt2', 'spruce'
-                       ], 'Line must be defined as Hlt2 or Sprucing line!'
-
     if process == 'spruce':
         pion = basic_builder.make_soft_pions(pi_pidk_max=None)
         proton = basic_builder.make_soft_protons(p_pidp_min=None)
@@ -46,11 +43,8 @@ def make_BuToLcmPPi_LcmToPKPi(process):
 ###########################################################
 # Form the B+ -> Lcbar- p+ K+, Lcbar- --> pbar K+ pi-
 ##########################################################
-@configurable
+@check_process
 def make_BuToLcmPK_LcmToPKPi(process):
-    assert process in ['hlt2', 'spruce'
-                       ], 'Line must be defined as Hlt2 or Sprucing line!'
-
     if process == 'spruce':
         kaon = basic_builder.make_soft_kaons(k_pidk_min=None)
         proton = basic_builder.make_soft_protons(p_pidp_min=None)