Fix typo (inversion between freq and values)

.gitignore

@@ -1 +1,2 @@
 .env
+__pycache__

src/science_signal/signal.py

@@ -66,10 +66,14 @@ class Signal:
             cos(self.y),
         )
 
-    def cut(self, start: float, end: float) -> "Signal":
+    def cut(self, start: None | float = None, end: None | float = None) -> "Signal":
         """
         Cut signal from a start x to an end x
         """
+        if start is None:
+            start = min(self.x)
+        if end is None:
+            end = max(self.x)
         indexes = where(logical_and(self.x > start, self.x < end))
         return Signal(
             self.x[indexes],
@@ -105,11 +109,16 @@ class Signal:
         )
 
     def filter(
-        self, start: None | float, end: None | float
+        self, start: None | float = None, end: None | float = None
     ) -> "Signal":
         freq_x = rfftfreq(len(self), self.sampling)
         freq_y = rfft(self.y)
 
+        if start is None:
+            start = min(abs(freq_x))
+        if end is None:
+            end = max(abs(freq_x))
+
         index_to_remove = where(
             logical_and(abs(freq_x) < start, abs(freq_x) > end)
         )
@@ -124,7 +133,7 @@ class Signal:
         """
         Compute psd of a given signal
         """
-        psd, freq = welch(
+        freq, psd = welch(
             self.y,
             self.rate,
             nperseg=fft_length * self.rate,