def axhline(self, y=<NUM_LIT:0>, xmin=<NUM_LIT:0>, xmax=<NUM_LIT:1>, **kwargs):
ymin, ymax = self.get_ybound()<EOL>yy = self.convert_yunits( y )<EOL>scaley = (yy<ymin) or (yy>ymax)<EOL>trans = mtransforms.blended_transform_factory(<EOL>self.transAxes, self.transData)<EOL>l = mlines.Line2D([xmin,xmax], [y,y], transform=trans, **kwargs)<EOL>l.x_isdata = False<EOL>self.add_line(l)<EOL>self.autoscale_view(scalex=False, scaley=scaley)<EOL>return l<EOL>
call signature::

  axhline(y=0, xmin=0, xmax=1, **kwargs)

Axis Horizontal Line

Draw a horizontal line at *y* from *xmin* to *xmax*.  With the
default values of *xmin* = 0 and *xmax* = 1, this line will
always span the horizontal extent of the axes, regardless of
the xlim settings, even if you change them, eg. with the
:meth:`set_xlim` command.  That is, the horizontal extent is
in axes coords: 0=left, 0.5=middle, 1.0=right but the *y*
location is in data coordinates.

Return value is the :class:`~matplotlib.lines.Line2D`
instance.  kwargs are the same as kwargs to plot, and can be
used to control the line properties.  Eg.,

* draw a thick red hline at *y* = 0 that spans the xrange

    >>> axhline(linewidth=4, color='r')

* draw a default hline at *y* = 1 that spans the xrange

    >>> axhline(y=1)

* draw a default hline at *y* = .5 that spans the the middle half of
  the xrange

    >>> axhline(y=.5, xmin=0.25, xmax=0.75)

Valid kwargs are :class:`~matplotlib.lines.Line2D` properties:

%(Line2D)s

.. seealso::
    :meth:`axhspan`:
        for example plot and source code