Error using matplotlib gallery examples in SageMath verbatim

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This is because Sage uses a preparser so that when you type:

a=2

Sage preparser replaces it with

a = Integer(2)

before sending it to Pytohn, so that a is a genuine integer, not a bare int.

The deque function does not support the Sage Integers, so you have to provide it a Python int. You can either do:

• tell the preparser not to touch the 500 in the definition of history_len :

  sage: history_len = 500r
  

• convert the Sage Integer back to a Python int:

  history_len = int(500)
  

• deactivate the preparser on the whole worksheet, by adding the following cell at the beginning of the worksheet:

  preparser(False)