address more pylint nitpicks

Author: Teque5

sigmf/convert/signalhound.py

@@ -76,7 +76,7 @@ def validate_spike(xml_path: Path) -> None:
     # validate CenterFrequency
     center_freq_raw = _text_of(root, "CenterFrequency")
     try:
-        center_frequency = float(center_freq_raw)
+        float(center_freq_raw)
     except (TypeError, ValueError) as err:
         raise SigMFConversionError(f"Invalid or missing CenterFrequency: {center_freq_raw}") from err
 

sigmf/sigmffile.py

@@ -1195,7 +1195,7 @@ def tofile(self, file_path, pretty: bool = True, overwrite: bool = False) -> Non
 
     def get_SigMFFile(self, stream_name=None, stream_index=None):
         """
-        Returns the SigMFFile instance of the specified stream if it exists
+        Returns the SigMFFile instance of the specified stream if it exists, or None.
         """
         if stream_name is not None and stream_name not in self.get_stream_names():
             # invalid stream name

tests/test_convert_blue.py

@@ -61,11 +61,11 @@ def tearDown(self) -> None:
         """clean up temporary directory"""
         self.tmp_dir.cleanup()
 
-    def write_minimal(self, format: bytes = b"CF") -> None:
+    def write_minimal(self, fmt: bytes = b"CF") -> None:
         """write minimal BLUE file to self.blue_path"""
 
-        is_complex = format[0] == ord(b"C")
-        dtype = TYPE_MAP[chr(format[1])]
+        is_complex = fmt[0] == ord(b"C")
+        dtype = TYPE_MAP[chr(fmt[1])]
 
         if np.issubdtype(dtype, np.integer):
             scale = 2 ** (np.dtype(dtype).itemsize * 8 - 1)
@@ -108,7 +108,7 @@ def write_minimal(self, format: bytes = b"CF") -> None:
             handle.write(b"BLUEEEEIEEEI")  # magic & endianness
             handle.seek(32)
             handle.write(
-                struct.pack("<ddi2s", 512, iq_converted.nbytes, 1000, format)
+                struct.pack("<ddi2s", 512, iq_converted.nbytes, 1000, fmt)
             )  # data_start, data_size, type, format
             handle.seek(56)
             handle.write(struct.pack("<d", self.timecode))  # timecode