Fix invalid escape sequence in binary_search_tree.py (#1920)

* Fix invalid escape sequence in binary_search_tree.py

data_structures/binary_tree/binary_search_tree.py:156
  /home/travis/build/TheAlgorithms/Python/data_structures/binary_tree/binary_search_tree.py:156: DeprecationWarning: invalid escape sequence \

* fixup! Format Python code with psf/black push

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

ciphers/a1z26.py

@@ -6,6 +6,7 @@ https://www.dcode.fr/letter-number-cipher
 http://bestcodes.weebly.com/a1z26.html
 """
 
+
 def encode(plain: str) -> list:
     """
     >>> encode("myname")
@@ -13,6 +14,7 @@ def encode(plain: str) -> list:
     """
     return [ord(elem) - 96 for elem in plain]
 
+
 def decode(encoded: list) -> str:
     """
     >>> decode([13, 25, 14, 1, 13, 5])
@@ -20,10 +22,12 @@ def decode(encoded: list) -> str:
     """
     return "".join(chr(elem + 96) for elem in encoded)
 
+
 def main():
     encoded = encode(input("->").strip().lower())
     print("Encoded: ", encoded)
     print("Decoded:", decode(encoded))
 
+
 if __name__ == "__main__":
     main()

data_structures/binary_tree/binary_search_tree.py

@@ -153,7 +153,7 @@ def postorder(curr_node):
 
 
 def binary_search_tree():
-    """
+    r"""
     Example
                   8
                  / \

digital_image_processing/test_digital_image_processing.py

@@ -78,7 +78,7 @@ def test_sepia():
     assert sepia.all()
 
 
-def test_burkes(file_path: str="digital_image_processing/image_data/lena_small.jpg"):
+def test_burkes(file_path: str = "digital_image_processing/image_data/lena_small.jpg"):
     burkes = bs.Burkes(imread(file_path, 1), 120)
     burkes.process()
     assert burkes.output_img.any()