decode_morse.py

r"""
>>> cases = [
...     ('', ''), ('  ', ''),
...     ('11 111 010 000 0', 'MORSE'),
...     ('11111 01111 00111 00011 00001', '01234'),
...     ('00000 10000 11000 11100 11110', '56789'),
... ]
...
>>> for stream, result in cases:
...     assert ''.join(decode_stream(stream)) == result
...
>>> for string, result in cases:
...     assert decode(string) == result
"""

from itertools import chain

def decode_char(code, table='..ETIANMSURWDKGOHVF.L.PJBXCYZQ..54.3...2.......16.......7...8.90'):
    return c if (c := table[code]) != '.' else None

def map_char(code):
    yield from [c] if (c := decode_char(code)) else []

def decode_stream(stream, code=1):
    if not stream:
        yield from map_char(code)
    elif (c := stream[0]) in '01':
        yield from decode_stream(stream[1:], code << 1 | int(c))
    else:
        yield from chain(map_char(code), decode_stream(stream[1:], 1))

def decode(string):
    return ''.join(decode_char(eval(f'0b1{code}')) for code in string.strip().split())

Below are equivalent:

eval(f'0b1{code}')
eval('0b1' + code)
int('1' + code, 2)
1 << len(code) | int(code, 2)