diff --git a/parser/parser/tokenizer.py b/parser/parser/tokenizer.py
index 60501fb..6250ce8 100644
--- a/parser/parser/tokenizer.py
+++ b/parser/parser/tokenizer.py
@@ -15,15 +15,17 @@ class Tokenizer:
         prev = None
 
         for ch in self.expression:
-            if (breaker_type := self.is_breaker(ch)) is not None:
+            if (breaker_type := Tokenizer.is_breaker(ch)) is not None:
                 if len(accumulator) > 0:
                     # ch is `(` after function name
-                    if breaker_type == Token.LBrace and self.is_function(accumulator):
+                    if breaker_type == Token.LBrace and Tokenizer.is_function(
+                        accumulator
+                    ):
                         yield accumulator, Token.Function
                         prev = Token.Function
                         accumulator = ""
                     else:
-                        value, token_type = self.detect_number(accumulator)
+                        value, token_type = Tokenizer.detect_number(accumulator)
                         yield value, token_type
                         prev = token_type
                         accumulator = ""