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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ValidateYesNoUnknown(value, column_name=None, problems=None):
 """Validates a value "0" for uknown, "1" for yes, and "2" for no."""

  if IsEmpty(value) or IsValidYesNoUnknown(value):
    return True
  else:
    if problems:
      problems.InvalidValue(column_name, value)
    return False