def justErrors(value):
"""Check value and ensure it contains no text, only errors (or nothing)."""
if not value:
return None
if not isinstance(value, list):
value = [value]
result = []
for part in flatten(value):
if part:
if not isinstance(part, Error):
raise Exception('Got %r when expecting only errors' % part)
else:
result.append(part)
return value
def stringsAndErrors(value):
"""Aggregate both unparsed strings and errors."""
if not value:
return None
if not isinstance(value, list):
value = [value]
result = []
lastStringPart = None
for part in flatten(value):
if isinstance(part, basestring):
lastStringPart = lastStringPart or StringIO.StringIO()
lastStringPart.write(part)
else:
if lastStringPart:
result.append(lastStringPart.getvalue())
lastStringPart = None
if part:
result.append(part)
if lastStringPart:
result.append(lastStringPart.getvalue())
return result