parameters: (self, b)
docstring: Read up to len(b) bytes into b.
  
          Returns number of bytes read (0 for EOF), or None if the object
          is set not to block and has no data to read.
docstring_summary: Read up to len(b) bytes into b.
docstring_tokens: Read up to len ( b ) bytes into b .
function: def readinto(self, b):
          """Read up to len(b) bytes into b.
  
          Returns number of bytes read (0 for EOF), or None if the object
          is set not to block and has no data to read.
          """
          self._unsupported("readinto")
function_tokens: def readinto ( self , b ) : self . _unsupported ( "readinto" )