code: def center(string, width, fillchar=" "):
      """Return a centered string of length determined by `line_width`
      that uses `fillchar` for padding.
      """
      left, right = center_pad(line_width(string), width, fillchar)
      return "".join([left, string, right])
  
imports: import sys
  import warnings
  from string import ascii_lowercase, ascii_uppercase
  import unicodedata
  from sympy.printing.conventions import split_super_sub
  from sympy.core.alphabets import greeks
  from sympy.utilities.exceptions import sympy_deprecation_warning
label_desc: Use image node_id 17 for calling a global function with example usage: center(string, width, fillchar) and returns: str