tests: lint wycheproof's python script

This PR lints tests_wycheproof_generate.py according to pylint.
This is a follow-up to PR bitcoin#1245.

Co-authored-by: Sean Andersen <6730974+andozw@users.noreply.github.com>

tools/tests_wycheproof_generate.py

@@ -7,8 +7,6 @@
 '''
 
 import json
-import hashlib
-import urllib.request
 import sys
 
 filename_input = sys.argv[1]
@@ -19,7 +17,8 @@
 num_groups = len(doc['testGroups'])
 
 def to_c_array(x):
-    if x == "": return ""
+    if x == "":
+        return ""
     s = ',0x'.join(a+b for a,b in zip(x[::2], x[1::2]))
     return "0x" + s
 
@@ -43,18 +42,23 @@ def to_c_array(x):
         sig_size = len(test_vector['sig']) // 2
         msg_size = len(test_vector['msg']) // 2
 
-        if test_vector['result'] == "invalid": expected_verify = 0
-        elif test_vector['result'] == "valid": expected_verify = 1
-        else: raise ValueError("invalid result field")
+        if test_vector['result'] == "invalid":
+            expected_verify = 0
+        elif test_vector['result'] == "valid":
+            expected_verify = 1
+        else:
+            raise ValueError("invalid result field")
 
-        if num_vectors != 0 and sig_size != 0: signatures += ",\n  "
+        if num_vectors != 0 and sig_size != 0:
+            signatures += ",\n  "
 
         new_msg = False
         msg = to_c_array(test_vector['msg'])
         msg_offset = offset_msg_running
         # check for repeated msg
-        if msg not in cache_msgs.keys():
-            if num_vectors != 0 and msg_size != 0: messages += ",\n  "
+        if msg not in cache_msgs:
+            if num_vectors != 0 and msg_size != 0:
+                messages += ",\n  "
             cache_msgs[msg] = offset_msg_running
             messages += msg
             new_msg = True
@@ -65,8 +69,9 @@ def to_c_array(x):
         pk = to_c_array(public_key['uncompressed'])
         pk_offset = offset_pk_running
         # check for repeated pk
-        if pk not in cache_public_keys.keys():
-            if num_vectors != 0: public_keys += ",\n  "
+        if pk not in cache_public_keys:
+            if num_vectors != 0:
+                public_keys += ",\n  "
             cache_public_keys[pk] = offset_pk_running
             public_keys += pk
             new_pk = True
@@ -76,15 +81,11 @@ def to_c_array(x):
         signatures += to_c_array(test_vector['sig'])
 
         out += "  /" + "* tcId: " + str(test_vector['tcId']) + ". " + test_vector['comment'] + " *" + "/\n"
-        out += "  {" + "{0}, {1}, {2}, {3}, {4}, {5}".format(
-                pk_offset,
-                msg_offset,
-                msg_size,
-                offset_sig,
-                sig_size,
-                expected_verify) + " },\n"
-        if new_msg: offset_msg_running += msg_size
-        if new_pk: offset_pk_running += 65
+        out += f"  {{{pk_offset}, {msg_offset}, {msg_size}, {offset_sig}, {sig_size}, {expected_verify} }},\n"
+        if new_msg:
+            offset_msg_running += msg_size
+        if new_pk:
+            offset_pk_running += 65
         offset_sig += sig_size
         num_vectors += 1
 
@@ -101,7 +102,7 @@ def to_c_array(x):
 
 
 print("/* Note: this file was autogenerated using tests_wycheproof_generate.py. Do not edit. */")
-print("#define SECP256K1_ECDSA_WYCHEPROOF_NUMBER_TESTVECTORS ({})".format(num_vectors))
+print(f"#define SECP256K1_ECDSA_WYCHEPROOF_NUMBER_TESTVECTORS ({num_vectors})")
 
 print(struct_definition)