parameters: (obj, freq, method=None, how=None, normalize=False, fill_value=None)
return_statement: return new_obj
docstring: Utility frequency conversion method for Series/DataFrame.
docstring_summary: Utility frequency conversion method for Series/DataFrame.
docstring_tokens: Utility frequency conversion method for Series / DataFrame .
function: def asfreq(obj, freq, method=None, how=None, normalize=False, fill_value=None):
      """
      Utility frequency conversion method for Series/DataFrame.
      """
      if isinstance(obj.index, PeriodIndex):
          if method is not None:
              raise NotImplementedError("'method' argument is not supported")
  
          if how is None:
              how = "E"
  
          new_obj = obj.copy()
          new_obj.index = obj.index.asfreq(freq, how=how)
  
      elif len(obj.index) == 0:
          new_obj = obj.copy()
          new_obj.index = obj.index._shallow_copy(freq=to_offset(freq))
  
      else:
          dti = date_range(obj.index[0], obj.index[-1], freq=freq)
          dti.name = obj.index.name
          new_obj = obj.reindex(dti, method=method, fill_value=fill_value)
          if normalize:
              new_obj.index = new_obj.index.normalize()
  
      return new_obj
function_tokens: def asfreq ( obj , freq , method = None , how = None , normalize = False , fill_value = None ) : if isinstance ( obj . index , PeriodIndex ) : if method is not None : raise NotImplementedError ( "'method' argument is not supported" ) if how is None : how = "E" new_obj = obj . copy ( ) new_obj . index = obj . index . asfreq ( freq , how = how ) elif len ( obj . index ) == 0 : new_obj = obj . copy ( ) new_obj . index = obj . index . _shallow_copy ( freq = to_offset ( freq ) ) else : dti = date_range ( obj . index [ 0 ] , obj . index [ - 1 ] , freq = freq ) dti . name = obj . index . name new_obj = obj . reindex ( dti , method = method , fill_value = fill_value ) if normalize : new_obj . index = new_obj . index . normalize ( ) return new_obj