How to use the formencode.validators.OneOf function in FormEncode

account_key_file_le_reg = FieldStorageUploadConverter(
        not_empty=False, if_missing=None
    )
    acme_account_provider_id = Int(not_empty=False, if_missing=None)
    private_key_option = OneOf(model_utils.PrivateKey_options_a, not_empty=True,)
    private_key_existing = UnicodeString(not_empty=False, if_missing=None)
    private_key_file_pem = FieldStorageUploadConverter(not_empty=False, if_missing=None)


class _form_AcmeAccount_PrivateKey_reuse(_form_AcmeAccount_PrivateKey_core):
    """this is a mix of two forms, because FormEncode doesn't support multiple class inheritance
    """

    account_key_option = OneOf(model_utils.AcmeAccontKey_options_b, not_empty=True,)
    account_key_reuse = UnicodeString(not_empty=False, if_missing=None)
    private_key_option = OneOf(model_utils.PrivateKey_options_b, not_empty=True,)
    private_key_reuse = UnicodeString(not_empty=False, if_missing=None)


class Form_AcmeAccount_edit(_Form_Schema_Base):

    # this is the `private_key_cycle` of the AcmeAccount
    account__private_key_cycle = OneOf(
        model_utils.PrivateKeyCycle._options_AcmeAccount_private_key_cycle,
        not_empty=True,
    )


class Form_AcmeAccount_new__auth(_Form_Schema_Base):
    acme_account_provider_id = Int(not_empty=True, if_missing=None)
    account__contact = Email(not_empty=True, if_missing=None)  # use it or don't

def _to_python(self, value, state):
    return [self.subvalidator.to_python(v)
            for v in str(value).split(self.separator)]

class PlatformValidator(formencode.FancyValidator):
  def _to_python(self, value, state):
    return platformList[str(value)]

class BaseLimit(object):
  """A base class which validates date/branch/product/version/buildid conditions for
  multiple searches."""

  datetime_validator = formencode.validators.Regex(
    '^\\d{4}-\\d{2}-\\d{2}( \\d{2}:\\d{2}(:\\d{2})?)?$', strip=True
  )
  range_unit_validator = formencode.validators.OneOf(
    rangeTypes.keys()
  )
  version_validator = ListValidator(ProductVersionValidator())
  stringlist_validator = ListValidator(formencode.validators.String(strip=True))
  platform_validator = ListValidator(PlatformValidator())
  query_validator = formencode.validators.OneOf(['signature', 'stack'])
  type_validator = formencode.validators.OneOf(['exact', 'startswith', 'contains'])
  signature_validator = formencode.validators.String(strip=True, if_empty=None)

  @staticmethod
  def limit_range(range):
    (num, unit) = range
    num = min(num * rangeTypes[unit], maxSearchHours) / rangeTypes[unit]
    return (num, unit)

  def __init__(self, date=None, range=None,

class _form_AcmeAccount_PrivateKey_reuse(_form_AcmeAccount_PrivateKey_core):
    """this is a mix of two forms, because FormEncode doesn't support multiple class inheritance
    """

    account_key_option = OneOf(model_utils.AcmeAccontKey_options_b, not_empty=True,)
    account_key_reuse = UnicodeString(not_empty=False, if_missing=None)
    private_key_option = OneOf(model_utils.PrivateKey_options_b, not_empty=True,)
    private_key_reuse = UnicodeString(not_empty=False, if_missing=None)


class Form_AcmeAccount_edit(_Form_Schema_Base):

    # this is the `private_key_cycle` of the AcmeAccount
    account__private_key_cycle = OneOf(
        model_utils.PrivateKeyCycle._options_AcmeAccount_private_key_cycle,
        not_empty=True,
    )


class Form_AcmeAccount_new__auth(_Form_Schema_Base):
    acme_account_provider_id = Int(not_empty=True, if_missing=None)
    account__contact = Email(not_empty=True, if_missing=None)  # use it or don't

    # this is the `private_key_cycle` of the AcmeAccount
    account__private_key_cycle = OneOf(
        model_utils.PrivateKeyCycle._options_AcmeAccount_private_key_cycle,
        not_empty=True,
    )

# these are via Form_AcmeAccount_new__file
    account_key_file_pem = FieldStorageUploadConverter(not_empty=False, if_missing=None)
    account_key_file_le_meta = FieldStorageUploadConverter(
        not_empty=False, if_missing=None
    )
    account_key_file_le_pkey = FieldStorageUploadConverter(
        not_empty=False, if_missing=None
    )
    account_key_file_le_reg = FieldStorageUploadConverter(
        not_empty=False, if_missing=None
    )
    acme_account_provider_id = Int(not_empty=False, if_missing=None)


class _form_PrivateKey_core(_Form_Schema_Base):
    private_key_option = OneOf(model_utils.PrivateKey_options_a, not_empty=True,)
    private_key_existing = UnicodeString(not_empty=False, if_missing=None)
    private_key_file_pem = FieldStorageUploadConverter(not_empty=False, if_missing=None)


class _form_AcmeAccount_reuse(_form_AcmeAccount_core):
    account_key_option = OneOf(model_utils.AcmeAccontKey_options_b, not_empty=True,)
    account_key_reuse = UnicodeString(not_empty=False, if_missing=None)


class _form_PrivateKey_reuse(_form_PrivateKey_core):
    private_key_option = OneOf(model_utils.PrivateKey_options_b, not_empty=True)
    private_key_reuse = UnicodeString(not_empty=False, if_missing=None)


class _form_AcmeAccount_PrivateKey_core(_Form_Schema_Base):
    """this is a mix of two forms, because FormEncode doesn't support multiple class inheritance

class ImportForm(formencode.Schema):
    """
    Validate for Import Connectivity Form
    """
    server_ip = validators.IPAddress(not_empty=True)
    username = validators.UnicodeString(not_empty=True)  
    password = validators.UnicodeString()
    threads_number = validators.Number()
    
    dti_scans = FileUploadValidator()
    
    subject_name = validators.UnicodeString()
    subject_sex = validators.OneOf(['Any', 'Male', 'Female'])  
    subject_age = validators.Number()
    subject_race = validators.UnicodeString()
    subject_nationality = validators.UnicodeString()
    subject_education = validators.UnicodeString()
    subject_health = validators.UnicodeString()

for xi in letsencrypt_info.CA_AUTH_X:
    Form_CACertificate_UploadBundle__file.add_field(
        "le_%s_auth_file" % xi,
        FieldStorageUploadConverter(not_empty=False, if_missing=None),
    )


class Form_Certificate_Upload__file(_Form_Schema_Base):
    private_key_file_pem = FieldStorageUploadConverter(not_empty=True)
    certificate_file = FieldStorageUploadConverter(not_empty=True)
    chain_file = FieldStorageUploadConverter(not_empty=True)


class Form_CoverageAssuranceEvent_mark(_Form_Schema_Base):
    action = OneOf(("resolution"), not_empty=True,)
    resolution = OneOf(
        model_utils.CoverageAssuranceResolution.OPTIONS_ALL, not_empty=True
    )


class Form_Domain_new(_Form_Schema_Base):
    domain_name = UnicodeString(not_empty=True)


class Form_Domain_mark(_Form_Schema_Base):
    action = OneOf(("active", "inactive"), not_empty=True)


class Form_Domain_search(_Form_Schema_Base):
    domain = UnicodeString(not_empty=True)

for xi in letsencrypt_info.CA_AUTH_X:
    Form_CACertificate_UploadBundle__file.add_field(
        "le_%s_auth_file" % xi,
        FieldStorageUploadConverter(not_empty=False, if_missing=None),
    )


class Form_Certificate_Upload__file(_Form_Schema_Base):
    private_key_file_pem = FieldStorageUploadConverter(not_empty=True)
    certificate_file = FieldStorageUploadConverter(not_empty=True)
    chain_file = FieldStorageUploadConverter(not_empty=True)


class Form_CoverageAssuranceEvent_mark(_Form_Schema_Base):
    action = OneOf(("resolution"), not_empty=True,)
    resolution = OneOf(
        model_utils.CoverageAssuranceResolution.OPTIONS_ALL, not_empty=True
    )


class Form_Domain_new(_Form_Schema_Base):
    domain_name = UnicodeString(not_empty=True)


class Form_Domain_mark(_Form_Schema_Base):
    action = OneOf(("active", "inactive"), not_empty=True)


class Form_Domain_search(_Form_Schema_Base):
    domain = UnicodeString(not_empty=True)

class Form_AcmeOrder_new_freeform(_form_AcmeAccount_PrivateKey_core):
    domain_names = UnicodeString(not_empty=True)
    processing_strategy = OneOf(
        model_utils.AcmeOrder_ProcessingStrategy.OPTIONS_ALL, not_empty=True,
    )

    # this is the `private_key_cycle` of the AcmeOrder renewals
    private_key_cycle__renewal = OneOf(
        model_utils.PrivateKeyCycle._options_AcmeOrder_private_key_cycle,
        not_empty=True,
    )


class Form_AcmeOrder_renew_quick(_Form_Schema_Base):
    processing_strategy = OneOf(
        model_utils.AcmeOrder_ProcessingStrategy.OPTIONS_ALL, not_empty=True,
    )


class Form_AcmeOrder_renew_custom(_form_AcmeAccount_PrivateKey_reuse):
    processing_strategy = OneOf(
        model_utils.AcmeOrder_ProcessingStrategy.OPTIONS_ALL, not_empty=True,
    )

    # this is the `private_key_cycle` of the AcmeOrder renewals
    private_key_cycle__renewal = OneOf(
        model_utils.PrivateKeyCycle._options_AcmeOrder_private_key_cycle,
        not_empty=True,
    )

def _modify_schema(schema):
    convert_from_tags = get_converter('convert_to_tags')
    convert_to_extras = get_converter('convert_to_extras')
    # Required fields
    schema['title'] = [not_empty, string_max_length(255), unicode]
    schema['notes'] = [not_empty, string_max_length(4000), unicode]
    schema['author'] = [not_empty, unicode]
    schema['resources']['name'] = [not_empty, string_max_length(255), unicode]
    # Add new fields
    schema[DATASET_TYPE_VOCABULARY] = [not_empty, convert_from_tags(DATASET_TYPE_VOCABULARY)]
    schema['temporal_extent'] = [ignore_missing, unicode, convert_to_extras]
    schema['affiliation'] = [ignore_missing, unicode, convert_to_extras]
    schema['contributors'] = [ignore_missing, unicode, convert_to_extras]
    schema['update_frequency'] = [ignore_missing, OneOf([v[0] for v in UPDATE_FREQUENCIES]), convert_to_extras, unicode]
    schema['promoted'] = [ignore_missing, convert_to_extras, boolean_validator]
    schema['spatial'] = [ignore_missing, convert_to_extras]