Changed warning in Arkane common.py to the string.format method

arkane/common.py

@@ -309,10 +309,9 @@ def check_conformer_energy(Vlist, path):
     Vlist = numpy.array(Vlist, numpy.float64)
     Vdiff = (Vlist[0] - numpy.min(Vlist)) * constants.E_h * constants.Na / 1000
     if Vdiff >= 2:  # we choose 2 kJ/mol to be the critical energy
-        logging.warning('the species corresponding to ' + str(os.path.basename(path))
-                        + ' is different in energy from the lowest energy conformer by '
-                        + "%0.2f" % Vdiff + ' kJ/mol. This can cause significant errors in your computed '
-                                            'rate constants. ')
+        logging.warning('the species corresponding to {path} is different in energy from the lowest energy conformer '
+                        'by {diff} kJ/mol. This can cause significant errors in your computed rate constants.'.format(
+                         path=os.path.basename(path), diff=Vdiff))
 
 
 def get_element_mass(input_element, isotope=None):