code: def _VmB (VmKey):
      
      if os.name != 'posix':
          # not supported
          return 0.0
      global _proc_status, _scale
      # get pseudo file /proc/<pid>/status
      try:
          t = open(_proc_status)
          v = t.read()
          t.close()
      except IOError:
          # unsupported platform (non-Linux?)
          return 0.0
      # get VmKey line e.g. 'VmRSS:  9999  kB\n ...'
      i = v.index(VmKey)
      v = v[i:].split(None, 3)  # whitespace
      if len(v) < 3:
          return 0.0  # invalid format?
      # convert Vm value to bytes
      return float(v[1]) * _scale[v[2]]
docs: Parse /proc/<pid>/status file for given key.
  
      @return: requested number value of status entry
      @rtype: float