fix flake8

Author: 88d52bdba0366127fffca9dfa93895

.flake8

@@ -1,3 +1,5 @@
 [flake8]
-max-line-length = 88
+max-line-length = 120
 extend-ignore = E203
+per-file-ignores =
+    tests/test_imports.py:F401

pypfopt/base_optimizer.py

@@ -591,10 +591,10 @@ def _get_all_args(expression: cp.Expression) -> List[cp.Expression]:
         return list(_flatten([_get_all_args(arg) for arg in expression.args]))
 
 
-def _flatten(l: Iterable) -> Iterable:
+def _flatten(alist: Iterable) -> Iterable:
     # Helper method to flatten an iterable
-    for el in l:
-        if isinstance(el, Iterable) and not isinstance(el, (str, bytes)):
-            yield from _flatten(el)
+    for v in alist:
+        if isinstance(v, Iterable) and not isinstance(v, (str, bytes)):
+            yield from _flatten(v)
         else:
-            yield el
+            yield v

pypfopt/cla.py

@@ -222,7 +222,7 @@ def _purge_num_err(self, tol):
                     if (
                         self.w[i][j] - self.lB[j] < -tol
                         or self.w[i][j] - self.uB[j] > tol
-                    ):  #  pragma: no cover
+                    ):  # pragma: no cover
                         flag = True
                         break
             if flag is True:

pypfopt/plotting.py

@@ -8,7 +8,6 @@
   - ``plot_efficient_frontier`` – plot the efficient frontier from an EfficientFrontier or CLA object
   - ``plot_weights`` - bar chart of weights
 """
-import copy
 import warnings
 
 import numpy as np