import base64
def parse_basic_auth(header_value):
""" Attempts to parse the given header value as a Base64-encoded Basic auth header. """
if not header_value:
return None
parts = header_value.split(' ')
if len(parts) != 2 or parts[0].lower() != 'basic':
try:
basic_parts = base64.b64decode(parts[1]).split(':', 1)
if len(basic_parts) != 2:
return basic_parts
except ValueError: