diff --git a/codebleu/codebleu.py b/codebleu/codebleu.py
index b35e597..e4d928f 100644
--- a/codebleu/codebleu.py
+++ b/codebleu/codebleu.py
@@ -79,7 +79,7 @@ def make_weights(reference_tokens, key_word_list):
         alpha * ngram_match_score
         + beta * weighted_ngram_match_score
         + gamma * syntax_match_score
-        + theta * (dataflow_match_score or 0)
+        + theta * (dataflow_match_score or 1.0)
     )
 
     return {
diff --git a/codebleu/dataflow_match.py b/codebleu/dataflow_match.py
index bcd89ac..2e4217b 100644
--- a/codebleu/dataflow_match.py
+++ b/codebleu/dataflow_match.py
@@ -1,6 +1,6 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT license.
-
+import logging
 from tree_sitter import Language, Parser
 
 from .parser import (
@@ -67,7 +67,7 @@ def corpus_dataflow_match(references, candidates, lang, langso_so_file):
                         match_count += 1
                         normalized_cand_dfg.remove(dataflow)
     if total_count == 0:
-        print(
+        logging.warning(
             "WARNING: There is no reference data-flows extracted from the whole corpus, "
             "and the data-flow match score degenerates to 0. Please consider ignoring this score."
         )
diff --git a/codebleu/weighted_ngram_match.py b/codebleu/weighted_ngram_match.py
index d03a04a..507cb76 100644
--- a/codebleu/weighted_ngram_match.py
+++ b/codebleu/weighted_ngram_match.py
@@ -192,7 +192,6 @@ def corpus_bleu(
     #       it tries to retain the Fraction object as much as the
     #       smoothing method allows.
     p_n = smoothing_function(p_n, references=references, hypothesis=hypothesis, hyp_len=hyp_lengths)
-    # pdb.set_trace()
     s = (w_i * math.log(p_i[0] / p_i[1]) for w_i, p_i in zip(weights, p_n))
     s = bp * math.exp(math.fsum(s))
     return s
@@ -212,7 +211,6 @@ def modified_recall(references, hypothesis, n):
     """
     # Extracts all ngrams in hypothesis
     # Set an empty Counter if hypothesis is empty.
-    # pdb.set_trace()
     numerator = 0
     denominator = 0
 
diff --git a/tests/test_codebleu.py b/tests/test_codebleu.py
index ec016cd..3875a94 100644
--- a/tests/test_codebleu.py
+++ b/tests/test_codebleu.py
@@ -2,6 +2,7 @@
 from typing import Any, List
 
 import pytest
+import logging
 
 from codebleu.codebleu import AVAILABLE_LANGS, calc_codebleu
 
@@ -16,7 +17,7 @@
 ])
 def test_simple_cases(predictions: List[Any], references: List[Any], codebleu: float) -> None:
     result = calc_codebleu(references, predictions, 'python')
-    print(result)
+    logging.debug(result)
     assert result['codebleu'] == pytest.approx(codebleu, 0.1)
 
 
@@ -37,7 +38,7 @@ def test_exact_match_works_for_all_langs(lang: str) -> None:
 ])
 def test_simple_cases_work_for_all_langs(lang: str, predictions: List[Any], references: List[Any]) -> None:
     result = calc_codebleu(references, predictions, lang)
-    print(result)
+    logging.debug(result)
     assert result['codebleu'] == pytest.approx(0.6, 0.1)
 
 
@@ -55,17 +56,17 @@ def test_error_when_input_length_mismatch() -> None:
     (
         ['public static int Sign ( double d ) { return ( float ) ( ( d == 0 ) ? 0 : ( c < 0.0 ) ? - 1 : 1) ; }'],
         ['public static int Sign ( double d ) { return ( int ) ( ( d == 0 ) ? 0 : ( d < 0 ) ? - 1 : 1) ; }'],
-        0.7238
+        0.7019
+    ),
+    (
+        ['public static int Sign ( double c ) { return ( int ) ( ( c == 0 ) ? 0 : ( c < 0 ) ? - 1 : 1) ; }'],
+        ['public static int Sign ( double d ) { return ( int ) ( ( d == 0 ) ? 0 : ( d < 0 ) ? - 1 : 1) ; }'],
+        0.8804
     ),
-    # (
-    #     ['public static int Sign ( double c ) { return ( int ) ( ( c == 0 ) ? 0 : ( c < 0 ) ? - 1 : 1) ; }'],
-    #     ['public static int Sign ( double d ) { return ( int ) ( ( d == 0 ) ? 0 : ( d < 0 ) ? - 1 : 1) ; }'],
-    #     0.8397
-    # ),
 ])
 def test_code_x_glue_readme_examples(predictions: List[Any], references: List[Any], codebleu: float) -> None:
     result = calc_codebleu(references, predictions, 'java')
-    print(result)
+    logging.debug(result)
     assert result['codebleu'] == pytest.approx(codebleu, 0.01)