Introduce black formatter (PyDMD#337)

Author: fandreuz

README.md

@@ -210,11 +210,11 @@ We'd love to accept your patches and contributions to this project. There are ju
      separate branches in order to ensure that a pull request only includes the
      commits related to that bug or feature.
 
-  3. To ensure properly formatted code, please make sure to use 4
-     spaces to indent the code. The easy way is to run on your bash the provided
-     script: ./code_formatter.sh. You should also run [pylint][] over your code.
-     It's not strictly necessary that your code be completely "lint-free",
-     but this will help you find common style issues.
+  3. To ensure properly formatted code, please run `black` on the files you edited.
+     You can install `black` with `pip3 install black`.
+     You should also run [pylint][] over your code. It's not strictly necessary
+     that your code be completely "lint-free", but this will help you find common
+     style issues.
 
   4. Any significant changes should almost always be accompanied by tests.  The
      project already has good test coverage, so look at some of the existing

code_formatter.sh

@@ -1,8 +1,21 @@
 """
 PyDMD init
 """
-__all__ = ['dmdbase', 'dmd', 'fbdmd', 'mrdmd', 'cdmd', 'hodmd', 'dmdc',
-           'optdmd', 'hankeldmd', 'rdmd', 'havok', 'bopdmd', 'pidmd']
+__all__ = [
+    "dmdbase",
+    "dmd",
+    "fbdmd",
+    "mrdmd",
+    "cdmd",
+    "hodmd",
+    "dmdc",
+    "optdmd",
+    "hankeldmd",
+    "rdmd",
+    "havok",
+    "bopdmd",
+    "pidmd",
+]
 
 
 from .meta import *