[CTI] Check for correct number of coverage parameters

This detects errors such as providing two sets of coverage parameters as a
single list, rather than as a list with separate entries for each set of
coverage parameters.

interfaces/cython/cantera/ctml_writer.py

@@ -1036,6 +1036,9 @@ class Arrhenius(rate_expression):
                 self._cov = [coverage]
             else:
                 self._cov = coverage
+            for cov in self._cov:
+                if len(cov) != 4:
+                    raise CTI_Error("Incorrect number of coverage parameters")
         else:
             self._cov = None