Add remove_member and remove_entry methods.

setup.py

@@ -10,7 +10,7 @@ def contents(*filenames):
 setup(
     name = "yangson",
     packages = ["yangson"],
-    version = "0.1.17",
+    version = "0.1.18",
     description = "Library for working with YANG schemas and data",
     author = "Ladislav Lhotka",
     author_email = "lhotka@nic.cz",

yangson/instance.py

@@ -211,10 +211,10 @@ class Instance:
         return inst
 
     def member(self, name: QName) -> "Instance":
-        obj = self.value.copy()
         try:
+            obj = self.value.copy()
             return Instance(obj.pop(name), MemberCrumb(name, obj, self.crumb))
-        except TypeError:
+        except (TypeError, AttributeError):
             raise InstanceTypeError(self, "member of non-object") from None
         except KeyError:
             raise NonexistentInstance(self, "member " + name) from None
@@ -225,6 +225,16 @@ class Instance:
         return Instance(value, MemberCrumb(name, self.value, self.crumb,
                                            datetime.now()))
 
+    def remove_member(self, name: QName) -> "Instance":
+        try:
+            val = self.value.copy()
+            del val[name]
+            return Instance(val, self.crumb)
+        except (TypeError, AttributeError):
+            raise InstanceTypeError(self, "member of non-object") from None
+        except KeyError:
+            raise NonexistentInstance(self, "member " + name) from None
+
     def sibling(self, name: QName) -> "Instance":
         try:
             obj = self.crumb.object.copy()
@@ -246,6 +256,15 @@ class Instance:
         except IndexError:
             raise NonexistentInstance(self, "entry " + str(index)) from None
 
+    def remove_entry(self, index: int) -> "Instance":
+        val = self.value
+        if not isinstance(val, list):
+            raise InstanceTypeError(self, "entry of non-array") from None
+        try:
+            return Instance(val[:index] + val[index+1:], self.crumb)
+        except IndexError:
+            raise NonexistentInstance(self, "entry " + str(index)) from None
+
     @property
     def first_entry(self):
         val = self.value