Corrected the error in functions

Author: RuchitJagodara

src/sage/groups/libgap_wrapper.pyx

@@ -347,7 +347,7 @@ class ParentLibGAP(SageObject):
 
     def minimal_normal_subgroups(self):
         """
-        Return a list containing those nontrivial normal subgroups of the group that are minimal among the nontrivial normal subgroups.
+        Return the nontrivial minimal normal subgroups ``self``.
 
         EXAMPLES::
 
@@ -357,12 +357,15 @@ class ParentLibGAP(SageObject):
              [0 6]
              ) of Special Linear Group of degree 2 over Finite Field in z2 of size 7^2]
         """
-        return [self._subgroup_constructor(gap_subgroup) for gap_subgroup in self.gap().MinimalNormalSubgroups()]
+        return [self._subgroup_constructor(gap_subgroup)
+                for gap_subgroup in self._libgap.MinimalNormalSubgroups()]
 
     def maximal_normal_subgroups(self):
         """
-        Return a list containing those proper normal subgroups of the group G that are maximal among the proper normal subgroups.
-        Gives error if G/G' is infinite, yielding infinitely many maximal normal subgroups.
+        Return the maximal proper normal subgroups of ``self``.
+
+        This raises an error if `G/[G, G]` is infinite, yielding infinitely
+        many maximal normal subgroups.
 
         EXAMPLES::
 
@@ -372,7 +375,8 @@ class ParentLibGAP(SageObject):
              [0 6]
              ) of Special Linear Group of degree 2 over Finite Field in z2 of size 7^2]
         """
-        return [self._subgroup_constructor(gap_subgroup) for gap_subgroup in self.gap().MaximalNormalSubgroups()]
+        return [self._subgroup_constructor(gap_subgroup)
+                for gap_subgroup in self._libgap.MaximalNormalSubgroups()]
 
     @cached_method
     def gens(self):

src/sage/groups/perm_gps/permgroup.py

@@ -4106,6 +4106,37 @@ def isomorphism_type_info_simple_group(self):
         else:
             raise TypeError("group must be simple")
 
+    def minimal_normal_subgroups(self):
+        """
+        Return the nontrivial minimal normal subgroups ``self``.
+
+        EXAMPLES::
+
+            sage: G = PermutationGroup([(1,2,3),(4,5)])
+            sage: G.minimal_normal_subgroups()
+            [Subgroup generated by [(4,5)] of (Permutation Group with generators [(4,5), (1,2,3)]),
+             Subgroup generated by [(1,2,3)] of (Permutation Group with generators [(4,5), (1,2,3)])]
+        """
+        return [self.subgroup(gap_group=gap_subgroup)
+                for gap_subgroup in self._libgap_().MinimalNormalSubgroups()]
+
+    def maximal_normal_subgroups(self):
+        """
+        Return the maximal proper normal subgroups of ``self``.
+
+        This raises an error if `G/[G, G]` is infinite, yielding infinitely
+        many maximal normal subgroups.
+
+        EXAMPLES::
+
+            sage: G = PermutationGroup([(1,2,3),(4,5)])
+            sage: G.maximal_normal_subgroups()
+            [Subgroup generated by [(1,2,3)] of (Permutation Group with generators [(4,5), (1,2,3)]),
+             Subgroup generated by [(4,5)] of (Permutation Group with generators [(4,5), (1,2,3)])]
+        """
+        return [self.subgroup(gap_group=gap_subgroup)
+                for gap_subgroup in self._libgap_().MaximalNormalSubgroups()]
+
     ######################  Boolean tests #####################
 
     def is_abelian(self):