Modified the reviewed part

Author: HenryWu2101

src/sage/matrix/matrix_gf2e_dense.pyx

@@ -965,7 +965,7 @@ cdef class Matrix_gf2e_dense(matrix_dense.Matrix_dense):
 
     def is_invertible(self):
         """
-        Return if invertible by checking full rank.
+        Return ``True`` if this matrix is invertible.
 
         EXAMPLES::
 
@@ -999,9 +999,10 @@ cdef class Matrix_gf2e_dense(matrix_dense.Matrix_dense):
         if not self.is_invertible():
             raise ZeroDivisionError("Matrix does not have full rank.")
 
-        sig_on()
-        mzed_invert_newton_john(A._entries, self._entries)
-        sig_off()
+        if self._nrows:
+            sig_on()
+            mzed_invert_newton_john(A._entries, self._entries)
+            sig_off()
 
         return A