original_string: private static function normalizeHeaders(array $headers): array
      {
          $normalizedHeaders = [];
  
          foreach ($headers as $name => $values) {
              if (\is_int($name)) {
                  [$name, $values] = explode(':', $values, 2);
                  $values = [ltrim($values)];
              } elseif (!\is_iterable($values)) {
                  $values = (array) $values;
              }
  
              $normalizedHeaders[$name = strtolower($name)] = [];
  
              foreach ($values as $value) {
                  $normalizedHeaders[$name][] = $value;
              }
          }
  
          return $normalizedHeaders;
      }
code: private static function normalizeHeaders(array $headers): array
      {
          $normalizedHeaders = [];
  
          foreach ($headers as $name => $values) {
              if (\is_int($name)) {
                  [$name, $values] = explode(':', $values, 2);
                  $values = [ltrim($values)];
              } elseif (!\is_iterable($values)) {
                  $values = (array) $values;
              }
  
              $normalizedHeaders[$name = strtolower($name)] = [];
  
              foreach ($values as $value) {
                  $normalizedHeaders[$name][] = $value;
              }
          }
  
          return $normalizedHeaders;
      }
code_tokens: private static function normalizeHeaders ( array $ headers ) : array { $ normalizedHeaders = [ ] ; foreach ( $ headers as $ name => $ values ) { if ( \ is_int ( $ name ) ) { [ $ name , $ values ] = explode ( ':' , $ values , 2 ) ; $ values = [ ltrim ( $ values ) ] ; } elseif ( ! \ is_iterable ( $ values ) ) { $ values = ( array ) $ values ; } $ normalizedHeaders [ $ name = strtolower ( $ name ) ] = [ ] ; foreach ( $ values as $ value ) { $ normalizedHeaders [ $ name ] [ ] = $ value ; } } return $ normalizedHeaders ; }
docstring: Normalizes headers by putting their names as lowercased keys.
  
  @return string[][]
docstring_tokens: Normalizes headers by putting their names as lowercased keys .