def METHOD_NAME(f: BinaryIO) -> CoffHeader:
    """Read the Common Object File Format (COFF) Header of the open file at `f`"""
    # Quote from the "PE Format" article (see [1] in this module's doc string):
    # "[...] at the file offset specified at offset 0x3c, is a 4-byte signature
    # that identifies the file as a PE format image file. This signature is
    # 'PE\0\0' (the letters "P" and "E" followed by two null bytes). [...]
    # immediately after the signature of an image file, is a standard COFF
    # file header in the following format."
    # Our `CoffHeader` embeds the signature inside the CoffHeader.
    f.seek(0x3c, io.SEEK_SET)
    buf = f.read(struct.calcsize("I"))
    (s, ) = struct.unpack_from("I", buf)
    f.seek(int(s), io.SEEK_SET)
    buf = f.read(struct.calcsize(CoffFormat))
    coff = CoffHeader._make(struct.unpack_from(CoffFormat, buf))
    assert coff.Signature == b"PE\0\0", "Not a PE32+ file (missing PE header)"
    return coff