code: def precision(key):
      """
      Relative precision in physical_constants indexed by key
  
      Parameters
      ----------
      key : Python string or unicode
          Key in dictionary `physical_constants`
  
      Returns
      -------
      prec : float
          Relative precision in `physical_constants` corresponding to `key`
  
      Examples
      --------
      >>> from scipy import constants
      >>> constants.precision(u'proton mass')
      5.1e-37
  
      """
      _check_obsolete(key)
      return physical_constants[key][2] / physical_constants[key][0]
  
file_path: catboost/contrib/python/scipy/py3/scipy/constants/codata.py
imports: import warnings
  from math import pi, sqrt
label_desc: Use image node_id 6 for calling a global function with example usage: precision(key) and returns: unknown