code: def _get_function_from_pyopengl(funcname):
      
      func = None
      
      # Get function from GL
      try:
          func = getattr(_GL, funcname)
      except AttributeError:
          # Get function from FBO
          try:
              func = getattr(_FBO, funcname)
          except AttributeError:
              func = None
      
      # Try using "alias"
      if not bool(func):
          # Some functions are known by a slightly different name
          # e.g. glDepthRangef, glClearDepthf
          if funcname.endswith('f'):
              try:
                  func = getattr(_GL, funcname[:-1])
              except AttributeError:
                  pass
  
      # Set dummy function if we could not find it
      if func is None:
          func = _make_unavailable_func(funcname)
          logger.warning('warning: %s not available' % funcname)
      return func
docs: Try getting the given function from PyOpenGL, return
      a dummy function (that shows a warning when called) if it
      could not be found.