Introduce Chars

This improves the implementation by introducing a class to manage the characters

src/ilp_keyboard_layout_optimization/receive_data.py

 """This module contains a class representing (special) character counts"""
 
-__all__ = ["CharacterCounts"]
+__all__ = ["CharProbs"]
 
 import csv
 from math import comb
@@ -8,11 +8,11 @@ from os.path import abspath, basename
 from typing import Optional
 from urllib.request import urlopen
 
-from .types import CharSet, CharTuple
+from src.ilp_keyboard_layout_optimization.type_aliases import CharSet, CharTuple
 
 
-class CharacterCounts:
-    """Instances represent all relevant (special) character counts
+class CharProbs:
+    """Instances represent all relevant (special) character probabilities
 
     Parameters
     ----------
@@ -120,11 +120,10 @@ class CharacterCounts:
                     row["bigram"][0] in self.chars and row["bigram"][1] in self.chars
                 ):
                     bi_probs[row["bigram"]] = absolute_count
-        total_sum = sum(bi_probs.values())
-        assert total_sum > 0
-        normalizer = 100 / total_sum
+        absolute_sum = sum(bi_probs.values())
         for character, count in bi_probs.items():
-            bi_probs[character] = count / normalizer
+            bi_probs[character] = count / absolute_sum
+        assert round(sum(bi_probs.values()), 8) == 1
         assert len(bi_probs) == reader.line_num or len(bi_probs) <= comb(
             reader.line_num, 2
         )
@@ -142,10 +141,10 @@ class CharacterCounts:
 
 
 if __name__ == "__main__":
-    CharacterCounts(
-        ("a", "b", "c"),
+    CharProbs(
+        None,
         "http://www.ids-mannheim.de/fileadmin/kl/derewo/"
         "DeReChar-v-uni-204-a-c-2018-02-28-1.0.csv",
         "http://practicalcryptography.com/media/cryptanalysis/files/"
-        "icelandic_bigrams.txt",
+        "german_bigrams.txt",
     )