Update src/sage/modules/free_module.py

Co-authored-by: Antoine Leudière <[email protected]>

Author: xcaruso

src/sage/modules/free_module.py

@@ -3156,6 +3156,16 @@ def pseudohom(self, f, twist, codomain=None, side="left"):
             f(\lambda x) = \theta(\lambda) f(x) + \delta(\lambda) x
 
         When `\delta` is nonzero, this requires that `M` coerces into `M'`.
+        .. WARNING::
+
+            At the moment, it is not possible to specify both a twisting
+            endomorphism and a twisting derivation. Only one of those can be
+            used, preferably using the `twist` argument.
+
+        We represent pseudo morphisms by matrices with coefficient in the base
+        ring `R`. See class
+        :class:`sage.modules.free_module_pseudomorphism.FreeModulePseudoMorphism`
+        for details.
 
         INPUT: