code: def validate_dpi(s):
      """Confirm s is string 'figure' or convert s to float or raise."""
      if s == "figure":
          return s
      try:
          return float(s)
      except ValueError as e:
          raise ValueError(
              f'{s!r} is not string "figure" and '
              f"could not convert {s!r} to float"
          ) from e
  
imports: import ast
  from functools import lru_cache, reduce
  from numbers import Real
  import operator
  import os
  import re
  import numpy
  from matplotlib import _api, cbook
  from matplotlib.cbook import ls_mapper
  from matplotlib.colors import Colormap, is_color_like
  from matplotlib._fontconfig_pattern import parse_fontconfig_pattern
  from matplotlib._enums import JoinStyle, CapStyle
  from cycler import Cycler, cycler
label_desc: Use image node_id 6 for calling a global function with example usage: validate_dpi(s) and returns: s, float