def step(self, x, y, *args, **kwargs):
where = kwargs.pop('<STR_LIT>', '<STR_LIT>')<EOL>if where not in ('<STR_LIT>', '<STR_LIT>', '<STR_LIT>'):<EOL><INDENT>raise ValueError("<STR_LIT>"<EOL>"<STR_LIT>")<EOL><DEDENT>kwargs['<STR_LIT>'] = '<STR_LIT>' + where<EOL>return self.plot(x, y, *args, **kwargs)<EOL>
call signature::

  step(x, y, *args, **kwargs)

Make a step plot. Additional keyword args to :func:`step` are the same
as those for :func:`~matplotlib.pyplot.plot`.

*x* and *y* must be 1-D sequences, and it is assumed, but not checked,
that *x* is uniformly increasing.

Keyword arguments:

*where*: [ 'pre' | 'post' | 'mid'  ]
  If 'pre', the interval from x[i] to x[i+1] has level y[i]

  If 'post', that interval has level y[i+1]

  If 'mid', the jumps in *y* occur half-way between the
  *x*-values.