Added different queries & unittests

src/cpl_query/extension/iterable_abc.py

@@ -0,0 +1,30 @@
+from abc import ABC, abstractmethod
+from typing import Optional, Callable
+
+
+class IterableABC(ABC, list):
+
+    @abstractmethod
+    def __init__(self):
+        list.__init__(self)
+
+    @abstractmethod
+    def any(self, func: str) -> bool: pass
+
+    @abstractmethod
+    def first(self) -> any: pass
+
+    @abstractmethod
+    def first_or_default(self) -> any: pass
+
+    @abstractmethod
+    def for_each(self, func: Callable): pass
+
+    @abstractmethod
+    def single(self): pass
+
+    @abstractmethod
+    def single_or_default(self) -> Optional[any]: pass
+
+    @abstractmethod
+    def where(self, func: str) -> 'IterableABC': pass