Introduced ParserInput

src/parsers/EmptyStringParser.py

@@ -1,4 +1,5 @@
 from core.builtin_concepts import BuiltinConcepts
+from core.sheerka.services.SheerkaExecute import ParserInput
 from parsers.BaseParser import BaseParser
 
 
@@ -10,12 +11,10 @@ class EmptyStringParser(BaseParser):
     def __init__(self, **kwargs):
         BaseParser.__init__(self, "EmptyString", 90)
 
-    def parse(self, context, parser_input):
+    def parse(self, context, parser_input: ParserInput):
         sheerka = context.sheerka
 
-        if isinstance(parser_input, str) and parser_input.strip() == "" or \
-            isinstance(parser_input, list) and parser_input == [] or \
-            parser_input is None:
+        if parser_input.is_empty():
             ret = sheerka.ret(self.name, True, sheerka.new(
                 BuiltinConcepts.PARSER_RESULT,
                 parser=self,