Ignored E252 error, minor flake8 fixes

.flake8

@@ -1,2 +1,4 @@
 [flake8]
 max-line-length = 120
+ignore =
+    E252

arca/backend/base.py

@@ -92,8 +92,9 @@ def get_setting(self, key, default=NOT_SET):
     def hash_file_contents(requirements_option: RequirementsOptions, path: Path) -> str:
         """ Returns a SHA256 hash of the contents of ``path`` combined with the Arca version.
         """
-        return hashlib.sha256(path.read_bytes() +
-                              bytes(requirements_option.name + arca.__version__, "utf-8")).hexdigest()
+        return hashlib.sha256(path.read_bytes() + bytes(
+            requirements_option.name + arca.__version__, "utf-8"
+        )).hexdigest()
 
     def get_requirements_information(self, path: Path) -> Tuple[RequirementsOptions, Optional[str]]:
         """

arca/backend/vagrant.py

@@ -184,7 +184,8 @@ def run_script(container_name, definition_filename, image_name, image_tag, repos
 
             api.run(f"docker cp /vagrant/{definition_filename} {container_name}:/srv/scripts/")
 
-            output = api.run(" ".join([
+            output = api.run(
+                " ".join([
                     "docker", "exec", container_name,
                     "python", "/srv/scripts/runner.py", f"/srv/scripts/{definition_filename}",
                 ]),

arca/result.py

@@ -17,7 +17,7 @@ def __init__(self, result: Union[str, Dict[str, Any]]) -> None:
                 raise BuildError("The build failed (the output was corrupted, "
                                  "possibly by the callable printing something)",
                                  extra_info={
-                                    "output": output
+                                     "output": output
                                  })
 
         if not isinstance(result, dict):