code: def series(expr, x=None, x0=0, n=6, dir="+"):
      """Series expansion of expr around point `x = x0`.
  
      Parameters
      ==========
  
      expr : Expression
             The expression whose series is to be expanded.
  
      x : Symbol
          It is the variable of the expression to be calculated.
  
      x0 : Value
           The value around which ``x`` is calculated. Can be any value
           from ``-oo`` to ``oo``.
  
      n : Value
          The number of terms upto which the series is to be expanded.
  
      dir : String, optional
            The series-expansion can be bi-directional. If ``dir="+"``,
            then (x->x0+). If ``dir="-", then (x->x0-). For infinite
            ``x0`` (``oo`` or ``-oo``), the ``dir`` argument is determined
            from the direction of the infinity (i.e., ``dir="-"`` for
            ``oo``).
  
      Examples
      ========
  
      >>> from sympy import series, tan, oo
      >>> from sympy.abc import x
      >>> f = tan(x)
      >>> series(f, x, 2, 6, "+")
      tan(2) + (1 + tan(2)**2)*(x - 2) + (x - 2)**2*(tan(2)**3 + tan(2)) +
      (x - 2)**3*(1/3 + 4*tan(2)**2/3 + tan(2)**4) + (x - 2)**4*(tan(2)**5 +
      5*tan(2)**3/3 + 2*tan(2)/3) + (x - 2)**5*(2/15 + 17*tan(2)**2/15 +
      2*tan(2)**4 + tan(2)**6) + O((x - 2)**6, (x, 2))
  
      >>> series(f, x, 2, 3, "-")
      tan(2) + (2 - x)*(-tan(2)**2 - 1) + (2 - x)**2*(tan(2)**3 + tan(2))
      + O((x - 2)**3, (x, 2))
  
      >>> series(f, x, 2, oo, "+")
      Traceback (most recent call last):
      ...
      TypeError: 'Infinity' object cannot be interpreted as an integer
  
      Returns
      =======
  
      Expr
          Series expansion of the expression about x0
  
      See Also
      ========
  
      sympy.core.expr.Expr.series: See the docstring of Expr.series() for complete details of this wrapper.
      """
      expr = sympify(expr)
      return expr.series(x, x0, n, dir)
  
label_desc: Use image node_id 1 for calling a global function with example usage: series(expr, x, x0, n, dir) and returns: expr