code: 
  '''simple docstring'''
  
  from typing import TYPE_CHECKING
  
  from ...utils import OptionalDependencyNotAvailable, _LazyModule, is_tokenizers_available, is_torch_available
  
  
  UpperCamelCase_     			=       {
      """configuration_realm""": ["""REALM_PRETRAINED_CONFIG_ARCHIVE_MAP""", """RealmConfig"""],
      """tokenization_realm""": ["""RealmTokenizer"""],
  }
  
  try:
       if not is_tokenizers_available():
            raise OptionalDependencyNotAvailable()
  except OptionalDependencyNotAvailable:
       pass
  else:
       UpperCamelCase_     			=       ["""RealmTokenizerFast"""]
  
  try:
       if not is_torch_available():
            raise OptionalDependencyNotAvailable()
  except OptionalDependencyNotAvailable:
       pass
  else:
       UpperCamelCase_     			=       [
           """REALM_PRETRAINED_MODEL_ARCHIVE_LIST""",
           """RealmEmbedder""",
           """RealmForOpenQA""",
           """RealmKnowledgeAugEncoder""",
           """RealmPreTrainedModel""",
           """RealmReader""",
           """RealmScorer""",
           """load_tf_weights_in_realm""",
       ]
       UpperCamelCase_     			=       ["""RealmRetriever"""]
  
  
  if TYPE_CHECKING:
       from .configuration_realm import REALM_PRETRAINED_CONFIG_ARCHIVE_MAP, RealmConfig
       from .tokenization_realm import RealmTokenizer
  
       try:
            if not is_tokenizers_available():
                 raise OptionalDependencyNotAvailable()
       except OptionalDependencyNotAvailable:
            pass
       else:
            from .tokenization_realm import RealmTokenizerFast
  
       try:
            if not is_torch_available():
                 raise OptionalDependencyNotAvailable()
       except OptionalDependencyNotAvailable:
            pass
       else:
            from .modeling_realm import (
                REALM_PRETRAINED_MODEL_ARCHIVE_LIST,
                RealmEmbedder,
                RealmForOpenQA,
                RealmKnowledgeAugEncoder,
                RealmPreTrainedModel,
                RealmReader,
                RealmScorer,
                load_tf_weights_in_realm,
            )
            from .retrieval_realm import RealmRetriever
  
  
  else:
       import sys
  
       UpperCamelCase_     			=       _LazyModule(__name__, globals()["""__file__"""], _import_structure, module_spec=__spec__)
  
  
  
style_context: 
  '''simple docstring'''
  
  def 	_UpperCAmelCase				(  _lowerCamelCase						:       int  ,      _lowerCamelCase						:       int  ,      _lowerCamelCase						:       int		)    ->						float:
    if common_ratio == 1:
      # Formula for sum if common ratio is 1
      return num_of_terms * first_term
  
    # Formula for finding sum of n terms of a GeometricProgression
    return (first_term / (1 - common_ratio)) * (1 - common_ratio**num_of_terms)
  
  
  