diff --git a/cashews/__init__.py b/cashews/__init__.py
index d55971e..9611fa0 100644
--- a/cashews/__init__.py
+++ b/cashews/__init__.py
@@ -7,7 +7,7 @@ from .decorators import (  # noqa
     fast_condition,
 )
 from .formatter import default_formatter, get_template_and_func_for, get_template_for_key  # noqa
-from .helpers import add_prefix  # noqa
+from .helpers import add_prefix, all_keys_lower  # noqa
 from .validation import set_invalidate_further  # noqa
 from .wrapper import Cache  # noqa
 
diff --git a/cashews/backends/redis/backend.py b/cashews/backends/redis/backend.py
index 5bdeffa..f33099c 100644
--- a/cashews/backends/redis/backend.py
+++ b/cashews/backends/redis/backend.py
@@ -198,8 +198,5 @@ class _Redis(Backend):
         return await self._client.get(key)
 
     def close(self):
-        del self._client
         self._client = None
         self.__is_init = False
-
-    __del__ = close
diff --git a/cashews/formatter.py b/cashews/formatter.py
index fef1406..9fd9bf9 100644
--- a/cashews/formatter.py
+++ b/cashews/formatter.py
@@ -18,7 +18,7 @@ class _ReplaceFormatter(Formatter):
             return self.__default(field_name), None
 
     def format_field(self, value, format_spec):
-        return format(value)
+        return format(format_value(value))
 
 
 class _FuncFormatter(_ReplaceFormatter):
@@ -38,9 +38,9 @@ class _FuncFormatter(_ReplaceFormatter):
 
     def format_field(self, value, format_spec):
         format_spec, args = self.parse_format_spec(format_spec)
-        value = super().format_field(value, format_spec if format_spec not in self._functions else "")
         if format_spec in self._functions:
-            return str(self._functions[format_spec](value, *args))
+            value = str(self._functions[format_spec](value, *args))
+        value = super().format_field(value, format_spec if format_spec not in self._functions else "")
         return value
 
     @staticmethod
@@ -51,6 +51,14 @@ class _FuncFormatter(_ReplaceFormatter):
         return format_spec, args.replace(")", "").split(",")
 
 
+def format_value(value):
+    if value is None:
+        return ""
+    elif isinstance(value, bool):
+        return str(value).lower()
+    return value
+
+
 default_formatter = _FuncFormatter(lambda name: "")
 default_formatter._register("len", len)
 
diff --git a/cashews/helpers.py b/cashews/helpers.py
index 0c15206..c61fd99 100644
--- a/cashews/helpers.py
+++ b/cashews/helpers.py
@@ -19,6 +19,23 @@ def add_prefix(prefix: str):
     return _middleware
 
 
+def all_keys_lower():
+    async def _middleware(call, *args, backend=None, cmd=None, **kwargs):
+        if cmd.lower() == "get_many":
+            return await call(*[key.lower() for key in args])
+        call_values = get_call_values(call, args, kwargs)
+        as_key = "key"
+        if cmd == "delete_match":
+            as_key = "pattern"
+        key = call_values.get(as_key)
+        if key:
+            call_values[as_key] = key.lower()
+            return await call(**call_values)
+        return await call(*args, **kwargs)
+
+    return _middleware
+
+
 def memory_limit(min=0, max=None):
     async def _memory_middleware(call, *args, backend=None, cmd=None, **kwargs):
         if cmd != "set":
diff --git a/cashews/key.py b/cashews/key.py
index 93a65a9..b8652cc 100644
--- a/cashews/key.py
+++ b/cashews/key.py
@@ -71,9 +71,8 @@ def _get_cache_key(
     """
     kwargs = kwargs or {}
     key_values = get_call_values(func, args, kwargs)
-    key_values = {k: v if v is not None else "" for k, v in key_values.items()}
     _key_template = template or get_cache_key_template(func)
-    return template_to_pattern(_key_template, _formatter=default_formatter, **key_values).lower()
+    return template_to_pattern(_key_template, _formatter=default_formatter, **key_values)
 
 
 def get_func_params(func):
@@ -100,7 +99,7 @@ def get_cache_key_template(func: Callable, key: Optional[str] = None, prefix: st
         if func_params and func_params[0] == "self":
             name = [func.__module__, func.__qualname__]
         params = {param_name: "{" + param_name + "}" for param_name in func_params}
-        key = ":".join([*name, *chain(*params.items())]).lower()
+        key = ":".join([*name, *chain(*params.items())])
     else:
         _check_key_params(key, func_params)
     if prefix:
diff --git a/cashews/serialize.py b/cashews/serialize.py
index aea1ecb..3affbb0 100644
--- a/cashews/serialize.py
+++ b/cashews/serialize.py
@@ -10,10 +10,6 @@ class UnSecureDataError(Exception):
     pass
 
 
-class none:
-    pass
-
-
 class PickleSerializerMixin:
     _digestmods = {
         b"sha1": hashlib.sha1,
@@ -47,7 +43,9 @@ class PickleSerializerMixin:
     def _process_value(self, value: Union[bytes, None, int, str], key, default=None):
         if value is None:
             return default
-        if isinstance(value, int) or value.isdigit():
+        if isinstance(value, int):
+            return value
+        if value.isdigit():
             return int(value)
         try:
             sign, value = value.split(b"_", 1)
@@ -60,8 +58,6 @@ class PickleSerializerMixin:
         value = pickle.loads(value, fix_imports=False, encoding="bytes")
         if self._check_repr:
             repr(value)
-        if value is none:
-            return None
         return value
 
     async def get_many(self, *keys):
@@ -86,8 +82,6 @@ class PickleSerializerMixin:
         return sign, digestmod
 
     async def set(self, key: str, value, *args, **kwargs):
-        if value is None:
-            value = none
         if isinstance(value, int) and not isinstance(value, bool):
             return await super().set(key, value, *args, **kwargs)
         value = pickle.dumps(value, protocol=pickle.HIGHEST_PROTOCOL, fix_imports=False)
diff --git a/cashews/validation.py b/cashews/validation.py
index ddb63d6..0d8bf99 100644
--- a/cashews/validation.py
+++ b/cashews/validation.py
@@ -11,7 +11,7 @@ from .key import get_call_values, get_func_params
 async def invalidate_func(backend: Backend, func, kwargs: Optional[Dict] = None):
     values = {**{param: "*" for param in get_func_params(func)}, **kwargs}
     for template in get_templates_for_func(func):
-        del_template = template_to_pattern(template, **values).lower()
+        del_template = template_to_pattern(template, **values)
         await backend.delete_match(del_template)
 
 

diff --git a/tests/test_key.py b/tests/test_key.py
index 6e8b99f..7b942cc 100644
--- a/tests/test_key.py
+++ b/tests/test_key.py
@@ -61,10 +61,10 @@ def test_cache_func_key_dict():
     ("args", "kwargs", "template", "key"),
     (
         (
-            ("a1", "a2", "a3"),
-            {"kwarg1": "k1", "kwarg3": "k3"},
+            ("A1", "a2", "a3"),
+            {"kwarg1": "k1", "kwarg3": True},
             "{arg1}:{kwarg1}-{kwarg3}",
-            "a1:k1-k3",
+            "A1:k1-true",
         ),
         (
             ("a1", "a2", "a3"),
@@ -92,9 +92,9 @@ def test_cache_func_key_dict():
         ),
         (
             ("a1",),
-            {"kwarg1": "k1", "arg2": 2},
+            {"kwarg1": "K1", "arg2": 2},
             "{arg2}:{kwarg1}:{kwarg3}",
-            "2:k1:",
+            "2:K1:",
         ),
         (("a1", "a2"), {"kwarg1": "test"}, "{kwarg1:len}", "4"),
         (
diff --git a/tests/test_wrapper.py b/tests/test_wrapper.py
index 6de9881..15f03d8 100644
--- a/tests/test_wrapper.py
+++ b/tests/test_wrapper.py
@@ -6,7 +6,7 @@ import pytest
 from cashews.backends.memory import Memory
 from cashews.disable_control import ControlMixin
 from cashews.formatter import get_templates_for_func
-from cashews.helpers import add_prefix
+from cashews.helpers import add_prefix, all_keys_lower
 from cashews.wrapper import Cache, _create_auto_init
 
 pytestmark = pytest.mark.asyncio
@@ -167,6 +167,22 @@ async def test_auto_init(cache):
     target.init.assert_called_once()
 
 
+async def test_all_keys_lower(cache: Cache, target):
+    cache._backends[""] = cache._backends[""][0], (all_keys_lower(),)
+    await cache.get(key="KEY")
+    target.get.assert_called_once_with(key="key", default=None)
+
+    await cache.set(key="KEY", value="value")
+    target.set.assert_called_once_with(
+        key="key",
+        value="value",
+        exist=None,
+        expire=None,
+    )
+    await cache.ping()
+    target.ping.assert_called_once_with(message=b"PING")
+
+
 async def test_add_prefix(cache: Cache, target):
     cache._backends[""] = cache._backends[""][0], (add_prefix("prefix!"),)
 

Case sensitive keys (do not convert silently all string arguments to lowercase by default)
I was surprised when I occasionally found that all strings are converted to lowercase when building a key. 
```python
import asyncio
import logging
from datetime import timedelta

from cashews import cache

logger = logging.getLogger(__name__)
logging.basicConfig(level="DEBUG")


async def logging_middleware(call, *args, backend=None, cmd=None, **kwargs):
    key = args[0] if args else kwargs.get("key", kwargs.get("pattern", ""))
    logger.info(f"{args}; {kwargs}")
    # logger.info("=> Cache request: %s ", cmd, extra={"command": cmd, "cache_key": key})
    return await call(*args, **kwargs)


cache.setup("mem://", middlewares=(logging_middleware, ))


@cache(ttl=timedelta(minutes=1))
async def get_name(user, version="v1"):
    return user


async def main():
    await get_name("Bob")
    result_1 = await get_name("Bob")
    result_2 = await get_name("bob")
    print(result_1)
    print(result_2)

    value = await cache.get("__main__:get_name:user:bob:version:v1")
    print(f"value: {value}")
    value = await cache.get("__main__:get_name:user:Bob:version:v1")
    print(f"value: {value}")


asyncio.run(main())
```
# Question

1. Is it a bug or a future?
2. Is there an easy way to disable strings lowercase when building a key? So if I pass `my_string=FooBar`, it will be saved as `FooBar`, not as `foobar`.
tests/test_wrapper.py::test_disable_cache_on_fail_return_2 tests/test_wrapper.py::test_disable_cmd tests/test_wrapper.py::test_init tests/test_wrapper.py::test_multilayer_cache tests/test_wrapper.py::test_all_keys_lower tests/test_wrapper.py::test_auto_init tests/test_wrapper.py::test_init_disable tests/test_wrapper.py::test_add_prefix_get_many tests/test_wrapper.py::test_disable_decorators_get tests/test_wrapper.py::test_disable_decorators_set tests/test_wrapper.py::test_cache_decor_register tests/test_wrapper.py::test_disable_ctz tests/test_wrapper.py::test_smoke_cmds tests/test_wrapper.py::test_disable_decorators tests/test_wrapper.py::test_prefix tests/test_wrapper.py::test_add_prefix_delete_match tests/test_wrapper.py::test_disable_cache_on_fail_return tests/test_wrapper.py::test_add_prefix tests/test_key.py::test_get_key_template[func2-None-tests.test_key:func2:a:{a}:k:{k}] tests/test_key.py::test_cache_key_args_kwargs[args10-kwargs10-{kwarg1:jwt(user)}-test] tests/test_key.py::test_ttl_to_seconds[10m1s-601] tests/test_key.py::test_get_key_template[func3-key:{k:len}:{k:hash(md5)}-key:{k:len}:{k:hash(md5)}] tests/test_key.py::test_cache_key_args_kwargs[args9-kwargs9-{kwarg1:hash(md5)}-098f6bcd4621d373cade4e832627b4f6] tests/test_key.py::test_detect_template_by_key[prefix:func1:test-func1:*] tests/test_key.py::test_ttl_to_seconds[<lambda>-3600_0] tests/test_key.py::test_detect_template_by_key[func2:user:1-None0] tests/test_key.py::test_detect_template_by_key[func1:-func1:*] tests/test_key.py::test_cache_key_args_kwargs[args0-kwargs0-{arg1}:{kwarg1}-{kwarg3}-A1:k1-true] tests/test_key.py::test_get_key_template[func1-None-tests.test_key:func1:a:{a}] tests/test_key.py::test_cache_key_args_kwargs[args4-kwargs4-{arg2}:{kwarg1}:{kwarg3}-2:k1:k3] tests/test_key.py::test_detect_template_by_key[func3:2-func3:*] tests/test_key.py::test_ttl_to_seconds[80-80] tests/test_key.py::test_ttl_to_seconds[1-1] tests/test_key.py::test_detect_template_by_key[func2:-:user:1-func2:*:user:*] tests/test_key.py::test_ttl_to_seconds[10-10] tests/test_key.py::test_cache_key_args_kwargs[args7-kwargs7-{user.name:len}-4] tests/test_key.py::test_cache_key_args_kwargs[args6-kwargs6-{kwarg1:len}-4] tests/test_key.py::test_detect_template_by_key[prefix:func2:test:user:1:1-None] tests/test_key.py::test_cache_key_args_kwargs[args5-kwargs5-{arg2}:{kwarg1}:{kwarg3}-2:K1:] tests/test_key.py::test_ttl_to_seconds[1m10s-70] tests/test_key.py::test_get_key_template[func3-None-tests.test_key:func3:a:{a}:k:{k}] tests/test_key.py::test_cache_func_key_dict tests/test_key.py::test_get_key_template_error tests/test_key.py::test_ttl_to_seconds[ttl0-10] tests/test_key.py::test_detect_template_by_key[func:1-None] tests/test_key.py::test_ttl_to_seconds[100.1-100.1] tests/test_key.py::test_ttl_to_seconds[10s-10] tests/test_key.py::test_cache_key_args_kwargs[args8-kwargs8-{kwarg1:hash}-098f6bcd4621d373cade4e832627b4f6] tests/test_key.py::test_ttl_to_seconds[<lambda>-3600_1] tests/test_key.py::test_detect_template_by_key[func1:test-func1:*] tests/test_key.py::test_cache_key_args_kwargs[args3-kwargs3-{arg2}-{kwarg1}-{kwarg3}-2-k1-] tests/test_key.py::test_cache_key_args_kwargs[args2-None-{arg1}-{kwarg1}-{kwarg3}-a1--] tests/test_key.py::test_detect_template_by_key[func2:user:1-None1] tests/test_key.py::test_cache_key_args_kwargs[args1-kwargs1-None-tests.test_key:func:arg1:a1:arg2:a2:kwarg1:k1:kwarg2:true] tests/test_key.py::test_get_key_template[func2-key:{k}-key:{k}]