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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 validate_instance(cls, opts):
 """Validates an instance of global options for cases that are not prohibited via registration. For example: mutually exclusive options may be registered by passing a `mutually_exclusive_group`, but when multiple flags must be specified together, it can be necessary to specify post-parse checks. Raises pants.option.errors.OptionsError on validation failure. """

    if opts.loop and (not opts.v2 or opts.v1):
      raise OptionsError('The --loop option only works with @console_rules, and thus requires '
                         '`--v2 --no-v1` to function as expected.')
    if opts.loop and not opts.enable_pantsd:
      raise OptionsError('The --loop option requires `--enable-pantsd`, in order to watch files.')

    if opts.v2_ui and not opts.v2:
      raise OptionsError('The --v2-ui option requires --v2 to be enabled together.')