Fix incorrect parsing in case of empty catch statement

slither/solc_parsing/declarations/function.py

@@ -511,6 +511,7 @@ class FunctionSolc(Function):
 
     def _parse_catch(self, statement, node):
         block = statement.get('block', None)
+
         if block is None:
             raise ParsingError('Catch not correctly parsed by Slither %s' % statement)
         try_node = self._new_node(NodeType.CATCH, statement['src'])
@@ -521,6 +522,7 @@ class FunctionSolc(Function):
         else:
             params = statement[self.get_children('children')]
 
+        if params:
             for param in params.get('parameters', []):
                 assert param[self.get_key()] == 'VariableDeclaration'
                 self._add_param(param)