Fix flake8 errors.

Signed-off-by: Tim 'mithro' Ansell <tansell@google.com>

v2x/lib/asserts.py

diff --git a/v2x/lib/asserts.py b/v2x/lib/asserts.py
index 8f5b4ad..b2d7b5c 100644
--- a/v2x/lib/asserts.py
+++ b/v2x/lib/asserts.py
@@ -60,14 +60,14 @@
         assert_type(obj, classes)
 
 
-def assert_len_eq(l):
+def assert_len_eq(v):
     """Check all lists in a list are equal length"""
     # Sanity check
-    max_len = max(len(p) for p in l)
-    for i, p in enumerate(l):
+    max_len = max(len(p) for p in v)
+    for i, p in enumerate(v):
         assert len(
             p
         ) == max_len, "Length check failed!\n \
-l[{}] has {} elements != {} ({!r})\n{!r}".format(
-            i, len(p), max_len, p, l
+v[{}] has {} elements != {} ({!r})\n{!r}".format(
+            i, len(p), max_len, p, v
         )

v2x/vlog_to_pbtype.py

diff --git a/v2x/vlog_to_pbtype.py b/v2x/vlog_to_pbtype.py
index 74fa32a..8c4f8c7 100755
--- a/v2x/vlog_to_pbtype.py
+++ b/v2x/vlog_to_pbtype.py
@@ -383,8 +383,8 @@
         else:
             return pin
 
-    for l in interconn.values():
-        l.sort(key=pin_sort)
+    for v in interconn.values():
+        v.sort(key=pin_sort)
 
     return interconn
 
@@ -452,7 +452,7 @@
     raise NameError("No cell named {}".format(shortname))
 
 
-def get_list_name_and_length(l: List[str]) -> Tuple[str, int]:
+def get_list_name_and_length(v: List[str]) -> Tuple[str, int]:
     """
     >>> get_list_name_and_length(['i[{}]'.format(i) for i in range(10)])
     ('i', 10)
@@ -502,21 +502,21 @@
     >>> get_list_name_and_length(['i[1][{}]'.format(i) for i in range(4)])
     ('i[1]', 4)
     """
-    if not l:
+    if not v:
         return True
 
-    assert '[' in l[0], "No index brackets found in item 0: {}\n{}".format(
-        l[0], l
+    assert '[' in v[0], "No index brackets found in item 0: {}\n{}".format(
+        v[0], v
     )
-    list_name = l[0][:l[0].rfind('[')]
-    sl = sorted(l, key=len)
-    for i in range(0, len(l)):
+    list_name = v[0][:v[0].rfind('[')]
+    sl = sorted(v, key=len)
+    for i in range(0, len(v)):
         expected_item = "{}[{}]".format(list_name, i)
         assert expected_item == sl[
             i], "index {} expected: {} != actual: {}\n{}".format(
                 i, expected_item, sl[i], sl
         )
-    return list_name, len(l)
+    return list_name, len(v)
 
 
 def make_ports(clocks, mod, pb_type_xml, only_type=None):
@@ -700,8 +700,8 @@
                 attrs["max"] = splitspec[1]
             else:
                 assert iodir == "input", \
-                    "Only input ports can have {} timing definition."
-                "Port {}, direction {}.".format(xmltype, port, iodir)
+                    ("Only input ports can have {} timing definition."
+                     "Port {}, direction {}.").format(xmltype, port, iodir)
                 attrs["value"] = splitspec[1]
             ET.SubElement(xml_parent, xmltype, attrs)
 

v2x/yosys/run.py

diff --git a/v2x/yosys/run.py b/v2x/yosys/run.py
index 2852133..25b4e82 100755
--- a/v2x/yosys/run.py
+++ b/v2x/yosys/run.py
@@ -110,7 +110,7 @@
         emsg += "Yosys failed with exit code {}\n".format(retcode)
         emsg += "Command: '{}'\n".format(" ".join(cmd))
         emsg += "Message:\n"
-        emsg += "\n".join([" " + l for l in stderr.splitlines()])
+        emsg += "\n".join([" " + v for v in stderr.splitlines()])
 
         raise subprocess.CalledProcessError(retcode, cmd, emsg)