ENH: Add custom exceptions for RocketPy library - UnstableRocketException

Author: Gui-FernandesBR

rocketpy/exceptions.py

@@ -0,0 +1,21 @@
+"""
+Custom exceptions for RocketPy library.
+"""
+
+
+class RocketPyException(Exception):
+    """All RocketPy custom exceptions should inherit from this class."""
+
+
+class UnstableRocketError(RocketPyException):
+    """Raised when the rocket jas negative static margin."""
+
+    def __init__(self, stability_margin):
+        self.stability_margin = stability_margin
+        self.message = (
+            "Rocket is unstable. Initial Static Margin is "
+            f"{stability_margin} calibers, this can lead to eternal loop simulation."
+        )
+
+    def __str__(self):
+        return self.message