Giving DtypeTuple the Dtype base class.

bitformat/_bits.py

@@ -1062,7 +1062,7 @@ def _format_bits(bits: Bits, bits_per_group: int, sep: str, dtype: Dtype | Dtype
                      colour_end: str,  width: int | None = None) -> tuple[str, int]:
         get_fn = dtype.unpack
         chars_per_group = Bits._chars_per_dtype(dtype, bits_per_group)
-        if isinstance(dtype, Dtype):
+        if not isinstance(dtype, DtypeTuple):
             if dtype.name == DtypeName.BYTES:  # Special case for bytes to print one character each.
                 get_fn = Bits._get_bytes_printable
             if  dtype.name == DtypeName.BOOL:  # Special case for bool to print '1' or '0' instead of `True` or `False`.
@@ -1098,7 +1098,7 @@ def _format_bits(bits: Bits, bits_per_group: int, sep: str, dtype: Dtype | Dtype
     @staticmethod
     def _chars_per_dtype(dtype: Dtype | DtypeTuple, bits_per_group: int):
         """How many characters are needed to represent a number of bits with a given Dtype."""
-        if isinstance(dtype, Dtype):
+        if not isinstance(dtype, DtypeTuple):
             return Register().name_to_def[dtype.name].bitlength2chars_fn(bits_per_group)
         # Start with '[' then add the number of characters for each element and add ', ' for each element, ending with a ']'.
         chars = sum(Bits._chars_per_dtype(d, bits_per_group) for d in dtype) + 2 + 2 * (len(dtype) - 1)

bitformat/_dtypes.py

@@ -605,7 +605,7 @@ def __str__(self) -> str:
         return f"[{self.base_dtype.name}{self.base_dtype.endianness.value}{size_str};{items_str}]"
 
 
-class DtypeTuple:
+class DtypeTuple(Dtype):
     """A data type class, representing a tuple of concrete interpretations of binary data.
 
     DtypeTuple instances are immutable. They are often created implicitly elsewhere via a token string.