fix lint errors

Author: SaraPido

sigpro/basic_primitives.py

@@ -28,10 +28,12 @@ class FFT(primitive.FrequencyTransformation):
     def __init__(self):
         super().__init__("sigpro.transformations.frequency.fft.fft")
 
+
 class FFTFreq(primitive.FrequencyTransformation):
-     """FFT Freq primitive class."""
-     def __init__(self):
-         super().__init__("sigpro.transformations.frequency.fftfreq.fft_freq")
+    """FFT Freq primitive class."""
+
+    def __init__(self):
+        super().__init__("sigpro.transformations.frequency.fftfreq.fft_freq")
 
 
 class FFTReal(primitive.FrequencyTransformation):

sigpro/transformations/frequency/fftfreq.py

@@ -16,4 +16,4 @@ def fft_freq(amplitude_values, sampling_frequency):
     """
     frequency_values = np.fft.fftfreq(len(amplitude_values), 1 / sampling_frequency)
 
-    return np.array(amplitude_values), np.array(frequency_values)
+    return np.array(amplitude_values), np.array(frequency_values)

tests/unit/transformations/frequency_time/test_stft.py

@@ -19,7 +19,7 @@ def test_stft():
     expected_time_values_len = 3
     value = amplitude_values[0][0]
 
-    assert type(value) == np.complex128
+    assert isinstance(value, np.complex128)
     assert len(amplitude_values) == expected_amplitude_values_len
     assert len(frequency_values) == expected_frequency_values_len
     assert len(time_values) == expected_time_values_len
@@ -39,7 +39,7 @@ def test_stft_real():
     expected_time_values_len = 3
     value = amplitude_values[0][0]
 
-    assert type(value) == np.float64
+    assert isinstance(value, np.float64)
     assert len(amplitude_values) == expected_amplitude_values_len
     assert len(frequency_values) == expected_frequency_values_len
     assert len(time_values) == expected_time_values_len