Formatting

* Adding black as dev dependency
* Formatting pina code
* Formatting tests

pina/optim/optimizer_interface.py

@@ -1,4 +1,4 @@
-""" Module for PINA Optimizer """
+"""Module for PINA Optimizer"""
 
 from abc import ABCMeta, abstractmethod
 
@@ -12,4 +12,4 @@ class Optimizer(metaclass=ABCMeta):  # TODO improve interface
 
     @abstractmethod
     def hook(self):
-        pass
+        pass