class Vocabulary(object):

    def __init__(self,
                 token_to_idx=None,
                 add_unk=True,
                 unk_token="<UNK>"):

        if token_to_idx is None:
            token_to_idx = {}
        self._token_to_idx = token_to_idx
        self._idx_to_token = {
            idx: token for token, idx in self._token_to_idx.items()
        }

        self._add_unk = add_unk
        self._unk_token = unk_token

        self.unk_index = -1
        if add_unk:
            self.unk_index = self.add_token(unk_token)

    def to_serializable(self):
        return {
            'token_to_idx': self._token_to_idx,
            'add_unk': self._add_unk,
            'unk_token': self._unk_token
        }

    @classmethod
    def from_serializable(cls, contents):
        return cls(**contents)

    def add_token(self, token):
        if token in self._token_to_idx:
            index = self._token_to_idx[token]
        else:
            index = len(self._token_to_idx)
            self._token_to_idx[token] = index
            self._idx_to_token[index] = token
        return index

    def add_many(self, tokens):
        return [self.add_token(token) for token in tokens]

    def lookup_token(self, token):

        if self.unk_index >= 0:
            return self._token_to_idx.get(token, self.unk_index)
        else:
            return self._token_to_idx[token]

    def lookup_index(self, index):

        if index not in self._idx_to_token:
            raise KeyError("the index (%d) is not in the Vocabulary" % index)
        return self._idx_to_token[index]

    def __str__(self):
        return "<Vocabulary(size=%d)>" % len(self)

    def __len__(self):
        return len(self._token_to_idx)
3ca4a8cce07910ec19c0f25df1ebec50ab83efaa
class Vocabulary(object):
    <mask token>

    def to_serializable(self):
        return {'token_to_idx': self._token_to_idx, 'add_unk': self.
            _add_unk, 'unk_token': self._unk_token}

    @classmethod
    def from_serializable(cls, contents):
        return cls(**contents)

    def add_token(self, token):
        if token in self._token_to_idx:
            index = self._token_to_idx[token]
        else:
            index = len(self._token_to_idx)
            self._token_to_idx[token] = index
            self._idx_to_token[index] = token
        return index

    def add_many(self, tokens):
        return [self.add_token(token) for token in tokens]
    <mask token>
    <mask token>

    def __str__(self):
        return '<Vocabulary(size=%d)>' % len(self)

    def __len__(self):
        return len(self._token_to_idx)

class Vocabulary(object):
    <mask token>

    def to_serializable(self):
        return {'token_to_idx': self._token_to_idx, 'add_unk': self.
            _add_unk, 'unk_token': self._unk_token}

    @classmethod
    def from_serializable(cls, contents):
        return cls(**contents)

    def add_token(self, token):
        if token in self._token_to_idx:
            index = self._token_to_idx[token]
        else:
            index = len(self._token_to_idx)
            self._token_to_idx[token] = index
            self._idx_to_token[index] = token
        return index

    def add_many(self, tokens):
        return [self.add_token(token) for token in tokens]

    def lookup_token(self, token):
        if self.unk_index >= 0:
            return self._token_to_idx.get(token, self.unk_index)
        else:
            return self._token_to_idx[token]
    <mask token>

    def __str__(self):
        return '<Vocabulary(size=%d)>' % len(self)

    def __len__(self):
        return len(self._token_to_idx)

class Vocabulary(object):

    def __init__(self, token_to_idx=None, add_unk=True, unk_token='<UNK>'):
        if token_to_idx is None:
            token_to_idx = {}
        self._token_to_idx = token_to_idx
        self._idx_to_token = {idx: token for token, idx in self.
            _token_to_idx.items()}
        self._add_unk = add_unk
        self._unk_token = unk_token
        self.unk_index = -1
        if add_unk:
            self.unk_index = self.add_token(unk_token)

    def to_serializable(self):
        return {'token_to_idx': self._token_to_idx, 'add_unk': self.
            _add_unk, 'unk_token': self._unk_token}

    @classmethod
    def from_serializable(cls, contents):
        return cls(**contents)

    def add_token(self, token):
        if token in self._token_to_idx:
            index = self._token_to_idx[token]
        else:
            index = len(self._token_to_idx)
            self._token_to_idx[token] = index
            self._idx_to_token[index] = token
        return index

    def add_many(self, tokens):
        return [self.add_token(token) for token in tokens]

    def lookup_token(self, token):
        if self.unk_index >= 0:
            return self._token_to_idx.get(token, self.unk_index)
        else:
            return self._token_to_idx[token]
    <mask token>

    def __str__(self):
        return '<Vocabulary(size=%d)>' % len(self)

    def __len__(self):
        return len(self._token_to_idx)

class Vocabulary(object):

    def __init__(self, token_to_idx=None, add_unk=True, unk_token='<UNK>'):
        if token_to_idx is None:
            token_to_idx = {}
        self._token_to_idx = token_to_idx
        self._idx_to_token = {idx: token for token, idx in self.
            _token_to_idx.items()}
        self._add_unk = add_unk
        self._unk_token = unk_token
        self.unk_index = -1
        if add_unk:
            self.unk_index = self.add_token(unk_token)

    def to_serializable(self):
        return {'token_to_idx': self._token_to_idx, 'add_unk': self.
            _add_unk, 'unk_token': self._unk_token}

    @classmethod
    def from_serializable(cls, contents):
        return cls(**contents)

    def add_token(self, token):
        if token in self._token_to_idx:
            index = self._token_to_idx[token]
        else:
            index = len(self._token_to_idx)
            self._token_to_idx[token] = index
            self._idx_to_token[index] = token
        return index

    def add_many(self, tokens):
        return [self.add_token(token) for token in tokens]

    def lookup_token(self, token):
        if self.unk_index >= 0:
            return self._token_to_idx.get(token, self.unk_index)
        else:
            return self._token_to_idx[token]

    def lookup_index(self, index):
        if index not in self._idx_to_token:
            raise KeyError('the index (%d) is not in the Vocabulary' % index)
        return self._idx_to_token[index]

    def __str__(self):
        return '<Vocabulary(size=%d)>' % len(self)

    def __len__(self):
        return len(self._token_to_idx)

class Vocabulary(object):

    def __init__(self,
                 token_to_idx=None,
                 add_unk=True,
                 unk_token="<UNK>"):

        if token_to_idx is None:
            token_to_idx = {}
        self._token_to_idx = token_to_idx
        self._idx_to_token = {
            idx: token for token, idx in self._token_to_idx.items()
        }

        self._add_unk = add_unk
        self._unk_token = unk_token

        self.unk_index = -1
        if add_unk:
            self.unk_index = self.add_token(unk_token)

    def to_serializable(self):
        return {
            'token_to_idx': self._token_to_idx,
            'add_unk': self._add_unk,
            'unk_token': self._unk_token
        }

    @classmethod
    def from_serializable(cls, contents):
        return cls(**contents)

    def add_token(self, token):
        if token in self._token_to_idx:
            index = self._token_to_idx[token]
        else:
            index = len(self._token_to_idx)
            self._token_to_idx[token] = index
            self._idx_to_token[index] = token
        return index

    def add_many(self, tokens):
        return [self.add_token(token) for token in tokens]

    def lookup_token(self, token):

        if self.unk_index >= 0:
            return self._token_to_idx.get(token, self.unk_index)
        else:
            return self._token_to_idx[token]

    def lookup_index(self, index):

        if index not in self._idx_to_token:
            raise KeyError("the index (%d) is not in the Vocabulary" % index)
        return self._idx_to_token[index]

    def __str__(self):
        return "<Vocabulary(size=%d)>" % len(self)

    def __len__(self):
        return len(self._token_to_idx)