code: def rc_params(usetex=None):
      
      # if user didn't specify to use tex or not, guess based on
      # the `GWPY_USETEX` environment variable, or whether tex is
      # installed at all.
      if usetex is None:
          usetex = bool_env(
              'GWPY_USETEX',
              default=rcParams['text.usetex'] or tex.has_tex())
  
      # build RcParams from matplotlib.rcParams with GWpy extras
      rcp = GWPY_RCPARAMS.copy()
      if usetex:
          rcp.update(GWPY_TEX_RCPARAMS)
      return rcp
docs: Returns a new `matplotlib.RcParams` with updated GWpy parameters
  
      The updated parameters are globally stored as
      `gwpy.plot.rc.GWPY_RCPARAMS`, with the updated TeX parameters as
      `gwpy.plot.rc.GWPY_TEX_RCPARAMS`.
  
      .. note::
  
         This function doesn't apply the new `RcParams` in any way, just
         creates something that can be used to set `matplotlib.rcParams`.
  
      Parameters
      ----------
      usetex : `bool`, `None`
          value to set for `text.usetex`; if `None` determine automatically
          using the ``GWPY_USETEX`` environment variable, and whether `tex`
          is available on the system. If `True` is given (or determined)
          a number of other parameters are updated to improve TeX formatting.
  
      Examples
      --------
      >>> import matplotlib
      >>> from gwpy.plot.rc import rc_params as gwpy_rc_params()
      >>> matplotlib.rcParams.update(gwpy_rc_params(usetex=False))