parameters: (line, ch)
return_statement: return i
docstring: Return number of `ch` characters at the start of `line`.
  
      Example:
  
      >>> _count_leading('   abc', ' ')
      3
docstring_summary: Return number of `ch` characters at the start of `line`.
docstring_tokens: Return number of ch characters at the start of line .
function: def _count_leading(line, ch):
      """
      Return number of `ch` characters at the start of `line`.
  
      Example:
  
      >>> _count_leading('   abc', ' ')
      3
      """
  
      i, n = 0, len(line)
      while i < n and line[i] == ch:
          i += 1
      return i
function_tokens: def _count_leading ( line , ch ) : i , n = 0 , len ( line ) while i < n and line [ i ] == ch : i += 1 return i