Force correct format of excluded frequency intervals

stingray/fourier.py

@@ -157,9 +157,14 @@ def power_color(
         power_err = np.asarray(power_err)
 
     if frequencies_to_exclude is not None:
-        if len(np.shape(frequencies_to_exclude)):
+        if len(np.shape(frequencies_to_exclude)) == 1:
             frequencies_to_exclude = [frequencies_to_exclude]
-        if np.shape(frequencies_to_exclude)[1] != 2:
+
+        if (
+            not isinstance(frequencies_to_exclude, Iterable)
+            or len(np.shape(frequencies_to_exclude)) != 2
+            or np.shape(frequencies_to_exclude)[1] != 2
+        ):
             raise ValueError("frequencies_to_exclude must be of format [[f0, f1], [f2, f3], ...]")
         for f0, f1 in frequencies_to_exclude:
             frequency_mask = (input_frequency_low_edges > f0) & (input_frequency_high_edges < f1)

stingray/tests/test_fourier.py

@@ -726,6 +726,11 @@ def test_bad_edges(self):
         with pytest.raises(ValueError, match="The maximum frequency is lower "):
             power_color(self.freq[good], self.power[good])
 
+    def test_bad_excluded_interval(self):
+        for fte in ([1, 1.1, 3.0], [4], [[1, 1.1, 3.0]], 0, [[[1, 3]]]):
+            with pytest.raises(ValueError, match="frequencies_to_exclude must be of "):
+                power_color(self.freq, self.power, frequencies_to_exclude=fte)
+
     def test_excluded_frequencies(self):
         pc0, _, pc1, _ = power_color(self.freq, self.power, frequencies_to_exclude=[1, 1.1])
         # The colors calculated with these frequency edges on a 1/f spectrum should be 1