Make Quantity more directly not default constructible

We are going to make `Quantity` a abstract base class, so we don't need
to do the trick to only allow to call the default constructor for the
`Quantity` class but not sub-classes. We just make `Quantity.__init__()`
always raise a `TypeError`, as subclasses can use `_new()` to create
instances.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

Author: llucax

src/frequenz/sdk/timeseries/_quantities.py

@@ -9,7 +9,7 @@
 
 import math
 from datetime import timedelta
-from typing import Any, NoReturn, Self, TypeVar, overload
+from typing import Self, TypeVar, overload
 
 QuantityT = TypeVar(
     "QuantityT",
@@ -41,14 +41,27 @@ class Quantity:
     class.  Sub-classes must define this.
     """
 
-    def __init__(self, value: float, exponent: int = 0) -> None:
-        """Initialize a new quantity.
+    def __init__(self) -> None:
+        """Initialize this instance.
 
-        Args:
-            value: The value of this quantity in a given exponent of the base unit.
-            exponent: The exponent of the base unit the given value is in.
+        This constructor is not meant to be used directly.  Use one of the `from_*()`
+        methods instead.
+
+        Raises:
+            TypeError: Every time this constructor is called.
         """
-        self._base_value = value * 10.0**exponent
+        # This is for documentation purposes and to hint to mypy that this
+        # attribute exists.
+        self._base_value: float = 0.0
+        """The value of this quantity in the base unit."""
+
+        cls = type(self)
+        raise TypeError(
+            "Use of default constructor is not allowed for "
+            f"{cls.__module__}.{cls.__qualname__}, "
+            f"use {cls.__name__}.zero() or one of the "
+            f"`{cls.__name__}.from_*()` constructors instead."
+        )
 
     @classmethod
     def _new(cls, value: float, *, exponent: int = 0) -> Self:
@@ -451,29 +464,8 @@ def __abs__(self) -> Self:
         return absolute
 
 
-class _NoDefaultConstructible(type):
-    """A metaclass that disables the default constructor."""
-
-    def __call__(cls, *_args: Any, **_kwargs: Any) -> NoReturn:
-        """Raise a TypeError when the default constructor is called.
-
-        Args:
-            *_args: ignored positional arguments.
-            **_kwargs: ignored keyword arguments.
-
-        Raises:
-            TypeError: Always.
-        """
-        raise TypeError(
-            "Use of default constructor NOT allowed for "
-            f"{cls.__module__}.{cls.__qualname__}, "
-            f"use one of the `{cls.__name__}.from_*()` methods instead."
-        )
-
-
 class Temperature(
     Quantity,
-    metaclass=_NoDefaultConstructible,
     exponent_unit_map={
         0: "°C",
     },
@@ -503,7 +495,6 @@ def as_celsius(self) -> float:
 
 class Power(
     Quantity,
-    metaclass=_NoDefaultConstructible,
     exponent_unit_map={
         -3: "mW",
         0: "W",
@@ -679,7 +670,6 @@ def __truediv__(self, other: Current | Voltage) -> Voltage | Current:
 
 class Current(
     Quantity,
-    metaclass=_NoDefaultConstructible,
     exponent_unit_map={
         -3: "mA",
         0: "A",
@@ -777,7 +767,6 @@ def __mul__(self, other: Percentage | Voltage) -> Self | Power:
 
 class Voltage(
     Quantity,
-    metaclass=_NoDefaultConstructible,
     exponent_unit_map={0: "V", -3: "mV", 3: "kV"},
 ):
     """A voltage quantity.
@@ -892,7 +881,6 @@ def __mul__(self, other: Percentage | Current) -> Self | Power:
 
 class Energy(
     Quantity,
-    metaclass=_NoDefaultConstructible,
     exponent_unit_map={
         0: "Wh",
         3: "kWh",
@@ -1032,7 +1020,6 @@ def __truediv__(self, other: timedelta | Power) -> Power | timedelta:
 
 class Frequency(
     Quantity,
-    metaclass=_NoDefaultConstructible,
     exponent_unit_map={0: "Hz", 3: "kHz", 6: "MHz", 9: "GHz"},
 ):
     """A frequency quantity.
@@ -1137,7 +1124,6 @@ def period(self) -> timedelta:
 
 class Percentage(
     Quantity,
-    metaclass=_NoDefaultConstructible,
     exponent_unit_map={0: "%"},
 ):
     """A percentage quantity.