code: def hazard_ratios_(self):
      return Series(
          np.exp(self.params_),
          index=self.params_.index,
          name="exp(coef)",
      )
  
file_path: lifelines/lifelines/fitters/mixins.py
imports: from typing import List, Optional, Dict, Any, Iterable
  from textwrap import dedent, fill
  from autograd import numpy
  import numpy
  from pandas import DataFrame, Series
  from lifelines.exceptions import ProportionalHazardAssumptionError
  from lifelines.statistics import proportional_hazard_test, TimeTransformers
  from lifelines.utils import format_p_value
  from lifelines.utils.lowess import lowess
label_desc: Use image node_id 2 for calling the ProportionalHazardMixin obj's underlying member method code with example usage: obj.hazard_ratios_() and returns: Series